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 the aerosol retention efficiency of a passive containment vessel of a nuclear power plant. The method comprises: obtaining geometric size data corresponding to a narrow gap in the passive containment vessel, internal pressure data of the containment vessel and environmental pressure data; analyzing the flow of aerosol in the narrow gap according to the geometric size data, the internal pressure data of the containment vessel and the environmental pressure data to obtain target along-flow data of the aerosol in the narrow gap and a target flow state of the aerosol in the narrow gap; and determining the aerosol retention efficiency corresponding to the narrow gap according to the target flow state, the target along-flow data and the geometric size data. The method can effectively calculate the effect of the narrow gap formed when the containment vessel is damaged on the retention of aerosol, and the accuracy of the evaluation of radioactive leakage can be improved by evaluating the radioactive leakage condition during an accident in combination with the aerosol retention efficiency obtained by the method.

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 related technologies, the assessment of radioactive aerosol leaks after a nuclear power plant accident often treats aerosols as gases, assuming that aerosols inside the containment vessel are released directly into the environment through cracks in the containment. This leads to inaccurate results in post-accident radioactivity assessments. Summary of the Invention

[0004] Therefore, it is necessary to provide a method and apparatus for determining the aerosol retention efficiency of a passive containment in a nuclear power plant, which can evaluate the retention efficiency of aerosols in the passive containment, in order to address the aforementioned 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] Acquire geometric data, containment pressure data, and ambient pressure data corresponding to the narrow slot on the passive containment.

[0007] The flow of aerosols in the narrow slit is analyzed based on geometric data, containment pressure data, and ambient pressure data to obtain the target flow data and target flow state of aerosols in the narrow slit.

[0008] Based on the target flow state, target flow data along the flow path, and geometric dimensions, determine the aerosol retention efficiency corresponding to the narrow slit.

[0009] In one embodiment, the geometric data includes the slit length; the flow of aerosols in the slit is analyzed based on the geometric data, containment pressure data, and ambient pressure data to obtain target flow data and target flow state of aerosols in the slit, including:

[0010] Based on the slit length, containment pressure data, and inlet Mach conjecture, the Mach number and pressure changes of each micro-element are calculated iteratively to obtain the intermediate flow data, intermediate flow state, outlet Mach value, and outlet pressure value of the aerosol in the slit.

[0011] If the calculated Mach number at the outlet does not indicate that the flow state inside the narrow slit is not choked flow and the calculated outlet pressure does not match the ambient pressure data, the inlet Mach conjecture value is updated, and the process of iteratively calculating the Mach number and pressure changes of each micro-element based on the narrow slit length, containment pressure data, and inlet Mach conjecture value is repeated to obtain the intermediate flow data of aerosols in the narrow slit, the calculated outlet Mach number at the narrow slit outlet, and the calculated outlet pressure value, until the calculated outlet Mach number equals one or the calculated outlet pressure value matches the ambient pressure data.

[0012] When the calculated Mach value at the outlet indicates that the flow state inside the narrow slot is choked flow, the target Mach value at the inlet is determined based on the calculated Mach value at the outlet. Based on the target Mach value at the inlet, the length of the narrow slot, and the pressure data inside the containment, the target flow data along the flow path and the target flow state are obtained.

[0013] When the calculated export pressure value matches the environmental pressure data, the intermediate flow data is determined as the target flow data, and the intermediate flow state is determined as the target flow state.

[0014] In one embodiment, the geometric data includes the slit diameter and the slit length;

[0015] Based on the target flow state, target flow data along the target path, and geometric dimensions, determine the aerosol retention efficiency corresponding to the narrow slot, including:

[0016] Determine the target deposition rate of aerosols within the narrow slit based on the target flow state;

[0017] Based on the target deposition rate, target flow data along the narrow gap, and narrow gap length, the target settling distance of aerosols in the narrow gap is determined;

[0018] The aerosol retention efficiency is determined based on the target settling distance and the slit diameter.

[0019] In one embodiment, determining the target deposition rate of the aerosol within the narrow slit based on the target flow state includes:

[0020] Under the condition that the target flow state is laminar or transitional flow, obtain the gravity deposition velocity of aerosols in the narrow slit;

[0021] Based on the gravity deposition velocity, the target deposition velocity corresponding to aerosols in the narrow slit is determined.

[0022] In one embodiment, the method further includes obtaining the Brownian diffusion velocity of the aerosol in the narrow slit during the process of obtaining the gravity deposition velocity of the aerosol in the narrow slit.

[0023] The target deposition velocity for aerosols in a narrow slit is determined based on gravity deposition velocity, including determining the target deposition velocity based on gravity deposition velocity and Brownian diffusion velocity.

[0024] In one embodiment, the aerosol retention efficiency is determined based on the target settling distance and the slit diameter, including:

[0025] The aerosol retention efficiency is determined based on the relationship between the target settling distance, the slit diameter, and the first retention efficiency.

[0026] In one embodiment, determining the target deposition rate of the aerosol within the narrow slit based on the target flow state includes:

[0027] Under the condition that the target flow state is turbulent, obtain the eddy collision deposition velocity of aerosols in the narrow slit;

[0028] Based on the eddy collision deposition velocity, the target deposition velocity of aerosols in the narrow slit is determined.

[0029] In one embodiment, the method further includes obtaining the eddy collision deposition velocity corresponding to the aerosol in the narrow slit: obtaining the eddy diffusion deposition velocity corresponding to the aerosol in the narrow slit.

[0030] The target deposition velocity of aerosols in a narrow slit is determined based on the eddy collision deposition velocity, including obtaining the target deposition velocity based on the eddy collision deposition velocity and the eddy diffusion deposition velocity.

[0031] In one embodiment, the aerosol retention efficiency is determined based on the target deposition distance and the slit diameter, including:

[0032] The aerosol retention efficiency is determined based on the relationship between the target settling distance, the narrow slit diameter, and the second retention efficiency.

[0033] Secondly, this application also provides a device for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, comprising:

[0034] The acquisition module is used to acquire geometric dimension data, containment pressure data, and ambient pressure data corresponding to the narrow slot on the passive containment.

[0035] The analysis module is used to analyze the flow of aerosols in the narrow slot based on geometric dimension data, containment pressure data and ambient pressure data, and to obtain the target flow data of aerosols along the narrow slot and the target flow state of aerosols in the narrow slot.

[0036] The determination module is used to determine the aerosol retention efficiency corresponding to the narrow slit based on the target flow state, target flow data along the flow path, and geometric dimension data.

[0037] The aforementioned method and apparatus for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant acquires geometrical data, containment pressure data, and ambient pressure data corresponding to narrow slots in the passive containment vessel. Based on these data, the flow of aerosols within the narrow slots is analyzed to obtain target flow data and target flow state of the aerosols within the slots. The aerosol retention efficiency corresponding to the narrow slots is then determined based on the target flow state, target flow data, and geometrical data. This embodiment, considering the ability to retain radioactive aerosols using narrow slots in the passive containment vessel without additional mechanical power, proposes a method to determine the aerosol retention efficiency of narrow slots in the passive containment vessel. This method can effectively calculate the aerosol retention effect of narrow slots formed when the containment vessel ruptures. Combining the aerosol retention efficiency obtained by this method with the assessment of radioactive leakage during an accident can improve the accuracy of radioactive leakage assessment. This, in turn, provides more accurate radioactive leakage assessment results for the economic viability of nuclear power plants and the site selection of new nuclear power plants. Attached Figure Description

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Figure 3 This is a flowchart illustrating the steps for obtaining target flow data and target flow state in one embodiment.

[0042] Figure 4 This is a schematic diagram of the friction Mach number and flow state in the narrow slot when the containment pressure is 2 bar, 3 bar, 4 bar, 5 bar and 6 bar respectively in one embodiment.

[0043] Figure 5This is a schematic diagram showing the Mach number and flow state along the narrow slit when the containment pressures are 1.1 bar, 1.3 bar, 1.5 bar, 1.7 bar and 1.9 bar, respectively, in one embodiment.

[0044] Figure 6 This is a flowchart illustrating the steps for determining the aerosol retention efficiency corresponding to a narrow slit in one embodiment.

[0045] Figure 7 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under the condition that the pressure inside the containment is 2 bar in one embodiment.

[0046] Figure 8 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under the condition that the pressure inside the containment is 3 bar in one embodiment.

[0047] Figure 9 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under the condition that the pressure inside the containment is 4 bar in one embodiment.

[0048] Figure 10 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under the condition that the pressure inside the containment is 5 bar in one embodiment.

[0049] Figure 11 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under the condition that the pressure inside the containment is 6 bar in one embodiment.

[0050] Figure 12 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under a containment pressure of 1.1 bar in one embodiment.

[0051] Figure 13 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under a containment pressure of 1.3 bar in one embodiment.

[0052] Figure 14 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under a containment pressure of 1.5 bar in one embodiment.

[0053] Figure 15 This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under a containment pressure of 11.7 bar in one embodiment.

[0054] Figure 16This is a schematic diagram showing the deposition rate at different locations within a narrow slit corresponding to different deposition types, under a containment pressure of 1.9 bar in one embodiment.

[0055] Figure 17 This is a schematic diagram of the aerosol retention area under the gravity settling mechanism in one embodiment;

[0056] Figure 18 This is a schematic diagram showing the gravitational settlement distance at different locations of the narrow slit in one embodiment;

[0057] Figure 19 This is a schematic diagram showing the vortex collision range at different locations of the narrow slit in one embodiment;

[0058] Figure 20 This is a schematic diagram of the vortex collision range at different locations of the narrow slit in another embodiment;

[0059] 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.

[0060] Figure 22 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0061] 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.

[0062] 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.

[0063] 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 1In 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.

[0064] 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 206. Wherein:

[0065] Step 202: Obtain the geometric dimensions, containment pressure, and ambient pressure data corresponding to the narrow slot on the passive containment.

[0066] In this embodiment, the containment slit is equivalent to a circular pipe because the meandering flow path and rough surface will lead to enhanced particle deposition and reduced aerosol leakage. Therefore, considering a straight pipe is conservative in engineering analysis, and the analysis results can be used to assess the leakage of radioactive aerosols.

[0067] The geometric dimensions of the narrow slot include the slot length and the slot diameter, where the slot length is equal to the shell thickness of the passive containment structure.

[0068] In one possible implementation, the slit diameter of the passive containment can be determined based on the size of the passive containment and the airflow velocity.

[0069] Engineering experience shows that when the upstream-to-downstream pressure ratio exceeds 1.89, airflow may reach a critical point (reaching the speed of sound 340 m / s). For example, in the event of an accident, the design absolute pressure inside the passive containment is 5.5 bar, the ambient pressure is 1 bar, and the upstream-to-downstream pressure ratio is 5.5, which exceeds the critical pressure ratio. Therefore, the airflow velocity is 340 m / s.

[0070] For example, the slit diameter is determined according to the method shown in formula (1).

[0071] , formula (1)

[0072] In formula (1), D is the diameter of the containment slot (m), and V is the free volume of the containment (m³). 3 ), It is the containment leakage rate, measured in seconds ( / s). It is the speed of airflow, and the unit is meters per second (m / s).

[0073] The containment pressure data are preset values ​​in the engineering design. For example, the range of containment pressure data is: 1 bar < absolute pressure inside the containment < 6 bar.

[0074] The ambient pressure data refers to the pressure outside the passive containment. For example, the ambient pressure data is 1 bar.

[0075] When a nuclear power plant accident occurs, the temperature and pressure inside the containment vessel rise rapidly. Radioactive aerosols carried by the atmosphere inside the containment vessel leak into the environment through cracks in the containment vessel, thus causing radioactive hazards to the public and the environment.

[0076] Step 204: Analyze the flow of aerosols in the narrow slit based on geometric data, containment pressure data, and ambient pressure data to obtain the target flow data and target flow state of aerosols in the narrow slit.

[0077] The target flow data refers to the flow velocity of the aerosol along the narrow slit. The target flow state refers to whether the flow state of the aerosol in the narrow slit is turbulent, laminar, or a transitional flow that is both.

[0078] When the leaked carrier gas is in laminar or transitional flow, aerosol particles in the carrier gas can be naturally removed through mechanisms such as gravity settling and Brownian diffusion. When the leaked carrier gas is in turbulent flow, aerosol particles in the carrier gas can be removed not only through gravity settling and Brownian diffusion, but also through turbulent collisions and turbulent diffusion.

[0079] 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 gas and move with the gas flow.

[0080] In the embodiments of this application, the target flow data and target flow state of the aerosol can also be referred to as the target flow data and target flow state corresponding to the carrier gas.

[0081] The flow state of the carrier gas in the narrow slit is related to the geometry of the narrow slit and the pressure difference between the upstream and downstream sides of the narrow slit. Therefore, in this embodiment, the flow of aerosol during unpacking is analyzed based on the geometry data of the narrow slit, the pressure data inside the containment, and the ambient pressure data to obtain the target flow data and target flow state of the aerosol, so as to assess the situation of the aerosol being trapped when passing through the unpacking.

[0082] Step 206: Determine the aerosol retention efficiency corresponding to the narrow slit based on the target flow state, target flow data along the flow path, and geometric dimension data.

[0083] Among them, based on the target flow state, it can be determined whether the aerosol undergoes gravity settling effect or turbulent collision effect when passing through the narrow gap, so as to determine the settling velocity.

[0084] Specifically, the flow velocity of aerosols in the narrow slit can be determined based on the target flow data. By combining the slit length and slit diameter, the final amount of aerosols retained in the slit can be calculated, thus determining the aerosol retention efficiency corresponding to the slit.

[0085] The method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant, provided in the above embodiments, acquires geometrical data, containment pressure data, and ambient pressure data corresponding to narrow slots in the passive containment vessel. Based on these data, the flow of aerosols within the narrow slots is analyzed to obtain target flow data and target flow state of the aerosols within the narrow slots. The aerosol retention efficiency corresponding to the narrow slots is then determined based on the target flow state, target flow data, and geometrical data. This embodiment considers the possibility of using narrow slots in the passive containment vessel to retain radioactive aerosols without additional mechanical power, and proposes a method to determine the aerosol retention efficiency of narrow slots in the passive containment vessel. This method can effectively calculate the aerosol retention effect of narrow slots formed when the containment vessel ruptures. Combining the aerosol retention efficiency obtained by this method with the assessment of radioactive leakage during an accident can improve the accuracy of radioactive leakage assessment. This, in turn, provides more accurate radioactive leakage assessment results for the economic viability of nuclear power plants and the site selection of new nuclear power plants.

[0086] 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 analyzing the flow of aerosols in a narrow slot based on geometric data, containment pressure data, and ambient pressure data to obtain target flow data and target flow state of the aerosols within the narrow slot. Figure 3 As shown, the process includes:

[0087] Step 302: Based on the narrow slit length, containment pressure data, and inlet Mach conjecture, iteratively calculate the Mach number and pressure changes of each micro-element to obtain the intermediate flow data, intermediate flow state, calculated outlet Mach value, and calculated outlet pressure value of the aerosol in the narrow slit.

[0088] Determine whether the calculated Mach number at the outlet indicates that the flow state within the narrow slit is not choked flow, and whether the calculated outlet pressure matches the environmental pressure data.

[0089] Step 304: If the calculated outlet Mach number indicates that the flow state within the narrow slit is not choked flow and the calculated outlet pressure does not match the ambient pressure data, update the inlet Mach number conjecture. Re-execute the iterative calculation of the Mach number and pressure changes for each micro-element based on the narrow slit length, containment pressure data, and the inlet Mach number conjecture, to obtain the intermediate flow data of the aerosol within the narrow slit, the calculated outlet Mach number at the slit outlet, and the calculated outlet pressure, until the calculated outlet Mach number equals one or the calculated outlet pressure matches the ambient pressure data.

[0090] Step 306: If the calculated Mach value at the outlet indicates that the flow state inside the narrow slot is choked flow, determine the target Mach value at the inlet based on the calculated Mach value at the outlet. Based on the target Mach value at the inlet, the length of the narrow slot, and the pressure data inside the containment, obtain the target flow data along the flow path and the target flow state.

[0091] Step 308: If the calculated outlet pressure value matches the environmental pressure data, the intermediate flow data is determined as the target flow data, and the intermediate flow state is determined as the target flow state.

[0092] For example, first, we conjecture the Mach number of the airflow at the slit inlet, i.e., the inlet Mach conjecture value (denoted as Ma1). We divide the slit into 100 equal micro-elements, assuming that the friction drag coefficient f in each micro-element is constant. We then calculate the Mach number increment in each micro-element using the Fanno function. (as shown in formula (2)) and pressure changes (As shown in formula (3)).

[0093] , formula (2)

[0094] , formula (3)

[0095] In formulas (2) and (3), is the specific heat ratio (taken as 1.4), Ma is the Mach number (the ratio of fluid velocity to local sound velocity), f is the friction coefficient (the friction factor between the pipe wall and the fluid), dx is the length of the infinitesimal pipe element (m), and G represents the dimensionless function of the Fanno flow, calculated as shown in formula (4):

[0096] , formula (4)

[0097] Then, based on formulas (2) to (4), the Mach number and pressure change of each micro-element are calculated iteratively until the exit of the narrow slit is reached. If the calculated Mach number at the exit (i.e. the calculated exit Mach value) is less than 1 and the calculated exit pressure is greater than the ambient pressure data, the inlet Mach conjecture value is increased until the calculated exit Mach value is equal to 1 or the calculated exit pressure value is equal to the ambient pressure data.

[0098] An example of the iterative calculation process is as follows:

[0099] First, calculate the inlet air density based on the upstream pressure. Then calculate the entrance sound velocity. Conjecture an entry Mach number, (Typical values ​​for noncritical flow). The inlet velocity is obtained. mass flow ;in This indicates the pressure data inside the containment vessel. This represents the temperature inside the containment, and R represents the gas constant. represents the specific heat ratio, and A represents the cross-sectional area of ​​the narrow slit.

[0100] Calculate infinitesimal segments The change in Mach number caused by friction. Calculate the Reynolds number, then calculate the coefficient of friction. (Using the Blasius formula and Fanning coefficient), the Fanno function G(Ma1) is calculated, and then... Change That is, the change in the van Nou function, the van Nou function of the new infinitesimal segment. Solve for the new Mach number (Through reverse calculation) Function): Substitution Function iteration yields .

[0101] Iteratively solve for the outlet Mach number of the next infinitesimal element, and calculate sequentially up to the outlet. Check whether the calculated outlet pressure value matches the ambient pressure data. If they do not match, increase the inlet Mach conjecture value until the calculated outlet pressure value matches the ambient pressure data or the outlet flow velocity reaches the critical value. Obtain the calculated outlet Mach number and the flow state along the pipe.

[0102] In this example, the inlet Mach conjecture value is guessed from a relatively small value. Also in this example, the calculated outlet pressure equals the ambient pressure data, indicating a match. In other examples, a match is considered to occur when the difference between the calculated outlet pressure and the ambient pressure data is less than a preset threshold.

[0103] In other examples, a smaller value can be guessed first, followed by a larger value, to facilitate rapid iteration. During this process, the calculated Mach value at the exit may be greater than 1, or the calculated Mach value of a certain microelement in the middle may reach 1 before the exit is calculated, thus ending the current iteration process and reducing the guessed Mach value at the entry.

[0104] In this example, a calculated exit Mach value of 1 indicates that the flow state of the carrier gas in the narrow slit is choked flow, and the flow velocity at the exit reaches the local speed of sound and will not increase further. In practical applications, due to factors such as calculation accuracy, a calculated exit Mach value of approximately 1 is sufficient to indicate that the flow state of the carrier gas in the narrow slit is choked flow. For example, if the calculated exit Mach value is between 0.995 and 1.005, the flow state of the carrier gas in the narrow slit is considered choked flow.

[0105] When the carrier gas flow is choked, the target inlet Mach value is derived from the calculated outlet Mach value. That is, the target inlet Mach value represents the actual Mach value at the inlet, rather than the previously guessed value. Then, based on the target inlet Mach value, the narrow slit length, and the pressure data inside the containment, the target flow data and the target flow state are obtained.

[0106] Specifically, the flow state corresponding to the slit in the current calculation process is determined based on the Reynolds number during the iterative calculation. For example, if the Reynolds number is less than 2300, the flow state is considered laminar; if the Reynolds number is greater than 2300 but less than 4000, the flow state is considered to be in the transition stage from laminar to turbulent, i.e., transitional flow; and if the Reynolds number is greater than 4000, the flow state is considered turbulent.

[0107] Please refer to Figure 4 and Figure 5 This study calculates and summarizes the distribution of Mach number and flow conditions along the narrow gap under different containment pressure data, with a narrow gap length of 1 meter, a narrow gap diameter of 3 mm, and an ambient pressure of 1 bar. Figure 4 The diagram shows the Mach number and flow state along the narrow gap when the pressure inside the containment is 2 bar, 3 bar, 4 bar, 5 bar and 6 bar. It is found that when the pressure inside the containment is greater than 2 bar, the flow state of the carrier gas in the narrow gap is turbulent in this example condition. Figure 5 The diagram illustrates the Mach number and flow state along the narrow gap when the containment pressure is 1.1 bar, 1.3 bar, 1.5 bar, 1.7 bar, and 1.9 bar, respectively. When the containment pressure is greater than 1.5 bar, the flow state of the carrier gas in the narrow gap is turbulent. In the two examples where the containment pressure is less than 1.5 bar, the flow state of the carrier gas in the narrow gap is transitional flow and transition from transitional flow to turbulent flow.

[0108] In one exemplary embodiment, based on Figure 2 In the illustrated embodiment, the geometric data includes the slit diameter and slit length. This embodiment relates to the process of determining the aerosol retention efficiency corresponding to the slit based on the target flow state, target flow data along the flow path, and geometric data. Figure 6 As shown, the process includes steps 602 to 606.

[0109] Step 602: Determine the target deposition rate of the aerosol within the narrow slit based on the target flow state.

[0110] In one possible implementation, when the target flow state is laminar or transitional, the gravity deposition velocity corresponding to the aerosol in the narrow slit is obtained; based on the gravity deposition velocity, the target deposition velocity corresponding to the aerosol in the narrow slit is determined.

[0111] For gravity settling, the sedimentation rate is determined by the final settling velocity of the spherical particles (Stokes' Law) as shown in Equation (5):

[0112] , formula (5)

[0113] In formula (5), g is the acceleration due to gravity. It is the gravitational relaxation time of the particle. For the density of particles, The particle diameter, This represents the Cunningham correction factor. This indicates the density of the gas. This indicates the dynamic viscosity of a gas.

[0114] In this implementation, when the target flow state is laminar or transitional, only the effect of gravity deposition on aerosol removal is considered. In this implementation, the target deposition velocity corresponding to the aerosol is equal to the gravity deposition velocity.

[0115] In one possible implementation, the method further includes obtaining the Brownian diffusion velocity of the aerosol in the narrow slit during the process of obtaining the gravity deposition velocity of the aerosol in the narrow slit; correspondingly, the process of determining the target deposition velocity of the aerosol in the narrow slit based on the gravity deposition velocity includes determining the target deposition velocity based on the gravity deposition velocity and the Brownian diffusion velocity.

[0116] In this embodiment, the target deposition rate is equal to the sum of the gravity deposition rate and the Brownian diffusion rate.

[0117] Brownian diffusion is caused by the thermal motion of molecules, and its sedimentation velocity is shown in formula (6):

[0118] , formula (6)

[0119] In formula (6), It refers to the boundary layer thickness, which is approximately 10. -5 m; is Boltzmann constant; T is the narrow slit carrier gas temperature, in Kelvin (K). This is the gas dynamic viscosity, measured in kg / (m•s). This represents the Cunningham correction factor. The particle diameter, This indicates the density of the gas. This indicates the dynamic viscosity of a gas.

[0120] In one possible implementation, when the target flow state is turbulent, the eddy collision deposition velocity corresponding to the aerosol in the narrow slit is obtained; based on the eddy collision deposition velocity, the target deposition velocity corresponding to the aerosol in the narrow slit is determined.

[0121] For eddy collisions, the corresponding deposition velocity can be expressed using the dimensionless particle relaxation time. This is represented as shown in formula (7):

[0122] , formula (7)

[0123] In formula (7), , This indicates the friction speed.

[0124] In this implementation, when the target flow is turbulent, only the turbulent collision mechanism is considered for its effect on aerosol removal. In this implementation, the target deposition velocity of the aerosol is equal to the eddy collision deposition velocity.

[0125] In one possible implementation, the method further includes: obtaining the eddy current collision deposition velocity corresponding to the aerosol in the narrow slit; and determining the target deposition velocity corresponding to the aerosol in the narrow slit based on the eddy current collision deposition velocity, including: obtaining the target deposition velocity based on the eddy current collision deposition velocity and the eddy current diffusion deposition velocity.

[0126] In this embodiment, the target deposition rate is equal to the sum of the eddy collision deposition rate and the eddy diffusion deposition rate.

[0127] In one possible implementation, the target deposition rate is equal to the sum of the eddy collision deposition rate, the eddy diffusion deposition rate, the gravity deposition rate, and the Brownian diffusion deposition rate.

[0128] The deposition rate caused by eddy diffusion is determined by formula (8):

[0129] , formula (8)

[0130] In formula (8), U is the axial airflow velocity, and f is the friction factor. Let represent the particle Schmitt number, and Re represent the Reynolds number.

[0131] Please refer to Figures 7 to 16 For the applicant's reference to the design of a typical pressurized water reactor, the aerosol particle size in the containment under accident conditions exhibits a normal distribution with a median mass diameter of 1.3 micrometers and a ensemble standard deviation of 1.81. Under the conditions of a slit length of 1 meter, a slit diameter of 3 mm, and an ambient pressure of 1 bar, the following schematic diagrams are derived and summarized to illustrate the deposition velocities at different locations within the slit corresponding to different deposition types under different containment pressure data. Figure 7 , Figure 8 , Figure 9 , Figure 10 and Figure 11 These are schematic diagrams showing the deposition velocities at different locations within the narrow slot for different deposition types, under containment pressures of 2 bar, 3 bar, 4 bar, 5 bar, and 6 bar. Figure 12 , Figure 13 , Figure 14 , Figure 15 and Figure 16 The diagram shows the deposition velocities at different locations within the narrow slot for different deposition types, under containment pressures of 1.1 bar, 1.3 bar, 1.5 bar, 1.7 bar, and 1.9 bar, respectively. Figures 7 to 16It can be seen that when the pressure inside the containment is low, the flow state of the carrier gas within the narrow slot of the containment is laminar or transitional, and the aerosol settling mechanism is gravity settling and Brownian diffusion. When the pressure inside the containment is high, turbulent diffusion and turbulent collision become the main aerosol settling mechanisms. Furthermore, analysis reveals that the higher the pressure inside the containment, the faster the carrier gas velocity in the narrow slot, and the faster the aerosol settling velocity.

[0132] Step 604: Based on the target deposition rate, target flow data along the narrow gap, and narrow gap length, determine the target deposition distance of aerosols in the narrow gap.

[0133] Specifically, based on the target deposition rate, target flow data along the path, and slit length, the distance that aerosols can ultimately settle when passing through the slit is calculated.

[0134] Step 606: Determine the aerosol retention efficiency based on the target settling distance and the slit diameter.

[0135] In one possible implementation, the target flow state is laminar or transitional flow. The process of determining the aerosol retention efficiency based on the target settling distance and the slit diameter includes: determining the aerosol retention efficiency according to the relationship between the target settling distance, the slit diameter, and the first retention efficiency.

[0136] Among them, the first retention efficiency relationship represents the relationship between the target settling distance, the slit diameter, and the aerosol retention efficiency when the target flow state is laminar or transitional.

[0137] For example, when the containment pressure is 1.1 bar, the carrier gas flow within the narrow slot is a transitional flow, and the primary settling mechanism is gravity settling. In this example, only the gravity settling velocity is considered. Based on the friction flow of the carrier gas and the gravity settling and friction flow velocities of the aerosols, the gravity settling distance D1 through the narrow slot is calculated. Since the direction of gravity settling is downward, aerosols in zone 1 will be trapped at the slot entrance. Figure 17 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 (9):

[0138] , formula (9)

[0139] In formula (9), D represents the slit diameter.

[0140] Please refer to Figure 18This is a schematic diagram showing the gravity settlement distance at different locations of the narrow slot, calculated by the applicant under the conditions of a narrow slot length of 1 meter, a narrow slot diameter of 3 mm, an ambient pressure of 1 bar, and a containment pressure of 1.1 bar, based on the particle model of aerosols in a typical pressurized water reactor model; (e.g.) Figure 18 As shown, the settlement distance in the entire narrow gap is 2.5E-5m, that is, D1=2.5E-5m, D=3E-3m, and the calculated target retention efficiency is 1.2%.

[0141] In one possible implementation, the target flow state is turbulent. The process of determining the aerosol retention efficiency based on the target settling distance and the slit diameter includes: determining the aerosol retention efficiency according to the relationship between the target settling distance, the slit diameter, and the second retention efficiency.

[0142] Among them, the second retention efficiency relationship represents the relationship between the target settling distance, the slit diameter, and the aerosol retention efficiency when the target flow state is turbulent.

[0143] For example, when the pressure inside the containment is 5 bar, the flow state of the carrier gas within the entire narrow slit is turbulent, and the main settling mechanism is eddy collision. In this example, only the eddy collision deposition velocity is considered. Based on the friction flow of the carrier gas and the eddy collision deposition velocity and friction flow velocity of the aerosol, the turbulent collision settling distance D2 when passing through the narrow slit is calculated. Since the turbulent collision direction is random, the second DC efficiency relationship can be expressed by integration, as shown in formula (10):

[0144] , formula (10)

[0145] In formula (10), D represents the slit diameter.

[0146] Please refer to Figure 19 This diagram illustrates the cumulative eddy collision range at different locations within a narrow slot, calculated by the applicant under conditions of a 1-meter slot length, a 3-mm slot diameter, an ambient pressure of 1 bar, and a containment pressure of 5 bar, based on a typical aerosol particle model in a pressurized water reactor. Only turbulent collision deposition velocities are considered; other deposition velocities are disregarded. Figure 19 As shown, the range in the entire narrow slit is approximately 8.7E-3m, i.e., D2=8.7E-3m, D=3E-3m. The range of the particles exceeds the diameter of the narrow slit cross section, so the target retention efficiency of the aerosol is considered to be 100%.

[0147] In one example, a schematic diagram of the cumulative eddy collision range at different locations of the narrow slit is calculated based on the particle model of aerosols in a typical pressurized water reactor model, under the conditions of a slit length of 1 meter, a slit diameter of 3 mm, an ambient pressure of 1 bar, and a containment pressure of 1.4 bar. When the containment pressure is 1.4 bar, the flow state of the carrier gas within the entire narrow slit is transitional flow at the front end and turbulent flow at the rear end. In the calculation process, laminar settling is ignored, and only turbulent deposition is considered. According to the second retention efficiency relationship shown in formula (10), the eddy collision range is calculated as follows: Figure 20 As shown, the range in the entire narrow slit is approximately 9.76E-4m, i.e., D2=8.7E-3m, D=3E-3m, and the target retention efficiency of the aerosol is 27%.

[0148] In one exemplary embodiment, a method for determining the aerosol retention efficiency of a passive containment vessel in a nuclear power plant is provided, which is then 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 including 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 S6. Wherein:

[0149] Step S2: Obtain the geometric dimensions, containment pressure, and ambient pressure data corresponding to the narrow slot on the passive containment. The geometric dimensions include the slot length and slot diameter.

[0150] Step S4: Based on the narrow slit length, containment pressure data, and inlet Mach conjecture, iteratively calculate the Mach number and pressure changes of each micro-element to obtain the intermediate flow data, intermediate flow state, calculated outlet Mach value, and calculated outlet pressure value of the aerosol in the narrow slit.

[0151] Step S6: If the calculated Mach number at the outlet does not indicate that the flow state inside the narrow slit is not choked flow and the calculated outlet pressure does not match the ambient pressure data, update the inlet Mach conjecture value and re-execute the iterative calculation of the Mach number and pressure change of each micro-element based on the narrow slit length, the containment pressure data, and the inlet Mach conjecture value to obtain the intermediate flow data of aerosols in the narrow slit, the calculated outlet Mach number at the narrow slit outlet, and the calculated outlet pressure value, until the calculated outlet Mach number equals one or the calculated outlet pressure value matches the ambient pressure data.

[0152] Step S8: If the calculated Mach value at the outlet indicates that the flow state inside the narrow slot is choked flow, determine the target Mach value at the inlet based on the calculated Mach value at the outlet. Based on the target Mach value at the inlet, the length of the narrow slot, and the pressure data inside the containment, obtain the target flow data along the flow path and the target flow state.

[0153] Step S10: If the calculated outlet pressure value matches the environmental pressure data, the intermediate flow data is determined as the target flow data, and the intermediate flow state is determined as the target flow state.

[0154] Step S12: Determine the target deposition rate of the aerosol within the narrow slit based on the target flow state.

[0155] Optionally, when the target flow state is laminar or transitional, the gravity deposition velocity and Brownian diffusion velocity corresponding to the aerosol in the narrow slit are obtained; based on the gravity deposition velocity and Brownian diffusion velocity, the target deposition velocity corresponding to the aerosol in the narrow slit is determined.

[0156] Optionally, when the target flow state is turbulent, the eddy collision deposition velocity and eddy diffusion deposition velocity corresponding to the aerosol in the narrow slit are obtained; based on the eddy collision deposition velocity and eddy diffusion deposition velocity, the target deposition velocity corresponding to the aerosol in the narrow slit is determined.

[0157] Step S14: Based on the target deposition rate, target flow data along the narrow slit, and slit length, determine the target deposition distance of aerosols in the narrow slit.

[0158] Step S16: Determine the aerosol retention efficiency based on the target settling distance and the slit diameter.

[0159] Optionally, when the target flow state is laminar or transitional, the aerosol retention efficiency is determined based on the relationship between the target settling distance, the slit diameter, and the first retention efficiency.

[0160] Optionally, when the target flow is turbulent, the aerosol retention efficiency is determined based on the relationship between the target settling distance, the slit diameter, and the second retention efficiency.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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: an acquisition module 2102, an analysis module 2104, and a determination module 2106, wherein:

[0165] The acquisition module 2102 is used to acquire geometric dimension data, containment pressure data and ambient pressure data corresponding to the narrow slot on the passive containment.

[0166] Analysis module 2104 is used to analyze the flow of aerosols in the narrow slit based on geometric dimension data, containment pressure data and ambient pressure data, and to obtain the target flow data of aerosols along the narrow slit and the target flow state of aerosols in the narrow slit.

[0167] The determination module 2106 is used to determine the aerosol retention efficiency corresponding to the narrow slit based on the target flow state, target flow data along the flow path, and geometric dimension data.

[0168] In an exemplary embodiment, the analysis module 2104 is used to iteratively calculate the Mach number and pressure changes of each micro-element based on the slit length, containment pressure data, and inlet Mach conjecture value, to obtain the intermediate flow data, intermediate flow state, calculated outlet Mach number, and calculated outlet pressure of the aerosol in the slit. If the calculated outlet Mach number indicates that the flow state in the slit is not choked flow and the calculated outlet pressure does not match the ambient pressure data, the inlet Mach conjecture value is updated, and the iterative calculation of the Mach number and pressure changes of each micro-element based on the slit length, containment pressure data, and inlet Mach conjecture value is re-executed to obtain... The process involves obtaining intermediate flow data of aerosols within a narrow slit, calculating the outlet Mach and outlet pressure at the slit outlet, until the calculated outlet Mach equals one or the calculated outlet pressure matches the ambient pressure data. If the calculated outlet Mach indicates that the flow state within the slit is choked flow, the target inlet Mach is determined based on the calculated outlet Mach. Based on the target inlet Mach, the slit length, and the containment pressure data, the target flow data and target flow state are obtained. If the calculated outlet pressure matches the ambient pressure data, the intermediate flow data is determined as the target flow data, and the intermediate flow state is determined as the target flow state.

[0169] In an exemplary embodiment, the geometric data includes the slit diameter and slit length; the determination module 2106 is used to determine the target deposition velocity corresponding to the aerosol in the slit based on the target flow state; to determine the target settling distance of the aerosol in the slit based on the target deposition velocity, the target flow data along the slit and the slit length; and to determine the aerosol retention efficiency based on the target settling distance and the slit diameter.

[0170] In an exemplary embodiment, the determining module 2106 is used to obtain the gravity deposition velocity corresponding to the aerosol in the narrow slit when the target flow state is laminar or transitional flow; and to determine the target deposition velocity corresponding to the aerosol in the narrow slit based on the gravity deposition velocity.

[0171] In an exemplary embodiment, the determining module 2106 is used to obtain the Brownian diffusion velocity corresponding to the aerosol in the slit; and to determine the target deposition velocity based on the gravity deposition velocity and the Brownian diffusion velocity.

[0172] In an exemplary embodiment, the determining module 2106 is used to determine the aerosol retention efficiency based on the relationship between the target settling distance, the slit diameter, and the first retention efficiency.

[0173] In an exemplary embodiment, the determining module 2106 is used to obtain the eddy collision deposition velocity corresponding to the aerosol in the narrow slit when the target flow state is turbulent; and to determine the target deposition velocity corresponding to the aerosol in the narrow slit based on the eddy collision deposition velocity.

[0174] In an exemplary embodiment, the determining module 2106 is used to obtain the eddy diffusion deposition velocity corresponding to the aerosol in the narrow slit; and to obtain the target deposition velocity based on the eddy collision deposition velocity and the eddy diffusion deposition velocity.

[0175] In an exemplary embodiment, the determining module 2106 is used to determine the aerosol retention efficiency based on the relationship between the target settling distance, the slit diameter, and the second retention efficiency.

[0176] 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.

[0177] 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.

[0178] Those skilled in the art will understand that Figure 22The 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining the aerosol retention efficiency of a passive containment in a nuclear power plant, characterized in that, The method includes: Acquire geometric data, containment pressure data, and ambient pressure data corresponding to the narrow slot on the passive containment. Based on the geometric dimension data, containment pressure data, and ambient pressure data, the flow of aerosols in the narrow slit is analyzed to obtain the target flow data and target flow state of aerosols in the narrow slit. Based on the target flow state, the target flow along the flow path, and the geometric dimensions, the aerosol retention efficiency corresponding to the narrow slit is determined.

2. The method according to claim 1, characterized in that, The geometric data includes the slit length; the analysis of aerosol flow in the slit based on the geometric data, containment pressure data, and ambient pressure data to obtain target flow data and target flow state of aerosols in the slit includes: Based on the narrow slit length, the containment pressure data, and the inlet Mach conjecture, the Mach number and pressure changes of each micro-element are iteratively calculated to obtain the intermediate flow data, intermediate flow state, outlet Mach calculation value, and outlet pressure calculation value of the aerosol in the narrow slit. If the calculated Mach number at the outlet indicates that the flow state within the narrow slit is not choked flow and the calculated outlet pressure does not match the ambient pressure data, the inlet Mach number conjecture is updated, and the process of iteratively calculating the Mach number and pressure changes of each micro-element based on the narrow slit length, the containment pressure data, and the inlet Mach number conjecture is repeated to obtain the intermediate flow data of the aerosol in the narrow slit, the calculated outlet Mach number at the narrow slit outlet, and the calculated outlet pressure, until the calculated outlet Mach number equals one or the calculated outlet pressure matches the ambient pressure data. When the calculated outlet Mach value indicates that the flow state inside the narrow slot is choked flow, the target inlet Mach value is determined based on the calculated outlet Mach value. Based on the target inlet Mach value, the narrow slot length, and the pressure data inside the containment, the target flow data along the flow path and the target flow state are obtained. If the calculated outlet pressure matches the environmental pressure data, the intermediate flow data is determined as the target flow data, and the intermediate flow state is determined as the target flow state.

3. The method according to claim 1, characterized in that, The geometric dimensions include the slit diameter and slit length; The step of determining the aerosol retention efficiency corresponding to the narrow slit based on the target flow state, target flow data along the flow path, and the geometric dimension data includes: Based on the target flow state, determine the target deposition rate of the aerosol within the narrow slit; Based on the target deposition rate, the target flow data along the path, and the slit length, the target settling distance of aerosols in the slit is determined; The aerosol retention efficiency is determined based on the target settling distance and the slit diameter.

4. The method according to claim 3, characterized in that, Determining the target deposition rate of the aerosol within the narrow slit based on the target flow state includes: When the target flow state is laminar or transitional, the gravity deposition velocity of the aerosol in the narrow slit is obtained; Based on the gravity deposition velocity, the target deposition velocity corresponding to the aerosol in the narrow slit is determined.

5. The method according to claim 4, characterized in that, In the process of obtaining the gravity deposition velocity corresponding to the aerosol in the narrow slit, the method further includes: obtaining the Brownian diffusion velocity corresponding to the aerosol in the narrow slit; Determining the target deposition velocity of aerosols in a narrow slit based on the gravity deposition velocity includes: determining the target deposition velocity based on the gravity deposition velocity and the Brownian diffusion velocity.

6. The method according to claim 4, characterized in that, Determining the aerosol retention efficiency based on the target settling distance and the slit diameter includes: The aerosol retention efficiency is determined based on the relationship between the target settling distance, the slit diameter, and the first retention efficiency.

7. The method according to claim 3, characterized in that, Determining the target deposition rate of the aerosol within the narrow slit based on the target flow state includes: When the target flow state is turbulent, the eddy collision deposition velocity of aerosols in the narrow slit is obtained; Based on the eddy collision deposition velocity, the target deposition velocity of aerosols in the narrow slit is determined.

8. The method according to claim 7, characterized in that, In the process of obtaining the eddy collision deposition velocity corresponding to the aerosol in the narrow slit, the method further includes: obtaining the eddy diffusion deposition velocity corresponding to the aerosol in the narrow slit; Determining the target deposition velocity of aerosols in a narrow slit based on the eddy collision deposition velocity includes: obtaining the target deposition velocity based on the eddy collision deposition velocity and the eddy diffusion deposition velocity.

9. The method according to claim 7, characterized in that, Determining the aerosol retention efficiency based on the target deposition distance and the slit diameter includes: The aerosol retention efficiency is determined based on the relationship between the target settling distance, the slit diameter, and the second retention efficiency.

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 acquisition module is used to acquire geometric dimension data, containment pressure data, and ambient pressure data corresponding to the narrow slot on the passive containment. The analysis module is used to analyze the flow of aerosols in the narrow slit based on the geometric dimension data, containment pressure data and ambient pressure data, and to obtain the target flow data of aerosols along the narrow slit and the target flow state of aerosols in the narrow slit. The determination module is used to determine the aerosol retention efficiency corresponding to the narrow slit based on the target flow state, the target flow data along the flow path, and the geometric dimension data.

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