Method and device for evaluating influence of radioactive substance release outside nuclear power field

Abstract

The embodiment of the invention provides an assessment method and device for nuclear power off-site radioactive substance release influence, and belongs to the technical field of nuclear power. The method comprises the following steps: acquiring an evaluation range for evaluating the release influence of radioactive substances, wherein the radioactive substances are released in a smoke plume form; within a preset evaluation duration, simulating the generation and movement process of the smoke plume within the evaluation range according to the meteorological condition of the release site, and obtaining the accumulated concentration and settlement concentration of the smoke plume; calculating according to the accumulated concentration and the settlement concentration to obtain the dose of air immersion external irradiation, the dose of surface external irradiation and the dose of suction internal irradiation in the evaluation range; and performing radiation evaluation according to the dose of the air immersion external irradiation, the dose of the surface external irradiation and the dose of the suction internal irradiation to obtain an evaluation result. According to the embodiment of the invention, migration, settlement, diffusion and other phenomena of the radioactive smoke plume in different areas outside the field can be tracked, influences of meteorological condition changes and settlement are coupled, and the accuracy of an evaluation result is improved.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and in particular, to a method and device for evaluating the impact of off-site radioactive material release in a nuclear power plant. Background Art

[0002] After a nuclear power plant accident occurs, core damage may lead to the release of radioactive materials from the containment into the environment. These radioactive materials will undergo phenomena such as migration, diffusion, and sedimentation under the influence of the off-site atmosphere of the nuclear power plant, thus affecting the real-time concentration distribution of off-site radioactive materials. After the release of radioactive materials, their migration, diffusion, and sedimentation processes are mainly affected by meteorological conditions (such as wind speed, wind direction, atmospheric stability, rainfall, etc.) around the nuclear power plant. When a radioactive plume moves in the atmosphere, its migration path and sedimentation area will change with the change of meteorological conditions. During the migration process of the plume, radioactive material sedimentation will occur in the passing areas, resulting in submersion external irradiation and ground surface external irradiation in local areas. In addition, the suspended radioactive materials in the plume may also be inhaled by the population on the ground surface, forming inhalation internal irradiation.

[0003] Currently, the off-site radioactive consequence assessment and nuclear emergency response system of nuclear power plants mainly uses the classical Gaussian plume model. However, this model cannot adapt to changing meteorological conditions, resulting in low accuracy of the assessment results. Summary of the Invention

[0004] The main purpose of the embodiments of this application is to propose a method and device for evaluating the impact of off-site radioactive material release in a nuclear power plant, aiming to solve the problem in the prior art that the accuracy of the assessment of the impact of off-site radioactive material release in a nuclear power plant is low due to the influence of changing meteorological conditions.

[0005] To achieve the above object, a first aspect of the embodiments of this application proposes a method for evaluating the impact of off-site radioactive material release in a nuclear power plant, the method including:

[0006] Obtain an evaluation range for evaluating the impact of radioactive material release, the evaluation range being determined according to the release location of the radioactive material, and the radioactive material being released in the form of a plume;

[0007] Within a preset evaluation duration, simulate the generation and movement process of the plume within the evaluation range according to the meteorological conditions at the release location, to obtain the cumulative concentration and sedimentation concentration of the plume, the cumulative concentration being the concentration obtained by accumulating the concentration in the evaluation range by the plume within the evaluation duration, and the sedimentation concentration being the concentration of the plume that settles onto the two-dimensional plane of the evaluation range after sedimentation;

[0008] Calculations are performed based on the cumulative concentration and the settling concentration to obtain the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation within the evaluation range;

[0009] Based on the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation, a radiation assessment is performed to obtain an assessment result.

[0010] In some embodiments, the evaluation duration includes multiple time periods;

[0011] There are multiple plumes;

[0012] Within the preset evaluation duration, the generation and movement processes of the plumes are simulated within the evaluation range according to the meteorological conditions at the release location to obtain the cumulative concentration and the settling concentration of the plumes, including:

[0013] The evaluation range is divided into a plurality of three-dimensional grids, and each three-dimensional grid corresponds to a three-dimensional space within the evaluation range;

[0014] For each of the multiple time periods in chronological order, the following processing is performed:

[0015] For any one of the multiple plumes, the generation and movement processes of the plume are simulated in the multiple three-dimensional grids according to the meteorological conditions at the release location to obtain the cumulative concentration and the settling concentration of the plume in the covered three-dimensional grids during the time period;

[0016] The cumulative concentration and the settling concentration of the plume in the covered three-dimensional grids obtained for each time period are respectively accumulated to obtain the cumulative concentration and the settling concentration of the plume.

[0017] In some embodiments, the meteorological conditions include the wind speed at the release location during the time period;

[0018] For any one of the multiple plumes, the generation and movement processes of the plume are simulated in the multiple three-dimensional grids according to the meteorological conditions at the release location to obtain the cumulative concentration and the settling concentration of the plume in the covered three-dimensional grids during the time period, including:

[0019] During the time period, the generation process of the plume is simulated in the multiple three-dimensional grids using a three-dimensional Gaussian distribution model to obtain the concentration distribution of the plume;

[0020] During the time period, the movement range of the plume is calculated to obtain the covered area of the plume;

[0021] Based on the covered area of the plume, the three-dimensional grids covered by the plume are determined;

[0022] Calculations are performed based on the wind speed during the said time period and the concentration distribution of the plume to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grid during the said time period.

[0023] In some embodiments, determining the three-dimensional grid covered by the plume according to the coverage area of the plume includes:

[0024] Obtain the three-dimensional coordinates of any three-dimensional grid;

[0025] If the three-dimensional coordinates are located in the coverage area of the plume, determine that the three-dimensional grid is the three-dimensional grid covered by the plume;

[0026] If the three-dimensional coordinates are not located in the coverage area of the plume, determine whether the three-dimensional coordinates of the next three-dimensional grid are located in the coverage area of the plume until all three-dimensional grids are traversed.

[0027] In some embodiments, the sedimentation concentration of the plume includes dry sedimentation concentration and wet sedimentation concentration;

[0028] The calculations performed based on the wind speed during the said time period and the concentration distribution of the plume to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grid during the said time period include:

[0029] Calculations are performed based on the wind speed during the said time period and the concentration distribution of the plume to obtain the cumulative concentration of the plume in the covered three-dimensional grid during the said time period;

[0030] Calculations are performed based on the wind speed during the said time period, the concentration distribution of the plume and the dry sedimentation rate to obtain the dry sedimentation concentration of the plume in the covered three-dimensional grid during the said time period;

[0031] Calculations are performed based on the wind speed during the said time period, the concentration distribution of the plume and the scavenging coefficient to obtain the wet sedimentation concentration of the plume in the covered three-dimensional grid during the said time period;

[0032] Calculations are performed based on the dry sedimentation concentration and wet sedimentation concentration of the plume in the covered three-dimensional grid during the said time period to obtain the sedimentation concentration of the plume in the covered three-dimensional grid during the said time period.

[0033] In some embodiments, the calculations performed based on the cumulative concentration and the sedimentation concentration to obtain the dose of external exposure by air immersion, the dose of external exposure on the ground surface and the dose of internal exposure by inhalation in the evaluation range include:

[0034] Calculating according to the shielding factor, the air immersion exposure dose rate conversion factor, the cumulative concentration and the deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of external exposure by air immersion in the three-dimensional grid covered by the plume during the time period;

[0035] Calculating according to the shielding factor, the external exposure dose rate conversion factor on the ground surface, the cumulative concentration and the deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of external exposure on the ground surface in the three-dimensional grid covered by the plume during the time period;

[0036] Calculating according to the breathing rate, the inhalation internal exposure dose rate conversion factor, the cumulative concentration and the deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of inhalation internal exposure in the three-dimensional grid covered by the plume during the time period.

[0037] In some embodiments, the step of adding up the cumulative concentration and the deposition concentration of the plume in the covered three-dimensional grid obtained in each time period respectively to obtain the cumulative concentration and the deposition concentration of the plume includes:

[0038] Obtaining the cumulative concentration of the plume in the three-dimensional grid in each time period and the deposition concentration of the plume in the three-dimensional grid in each time period according to the coordinates of the three-dimensional grid covered by the plume;

[0039] Adding up the cumulative concentrations in each time period in each three-dimensional grid covered by the plume to obtain the cumulative concentration of the plume;

[0040] Adding up the deposition concentrations in each time period in each three-dimensional grid covered by the plume to obtain the deposition concentration of the plume.

[0041] In some embodiments, the step of performing radiation assessment according to the dose of external exposure by air immersion, the dose of external exposure on the ground surface and the dose of inhalation internal exposure to obtain an assessment result includes:

[0042] Evaluating the dose of external exposure by air immersion according to a preset first dose index to obtain the pollution level of the dose of external exposure by air immersion, where the first dose index is used to indicate the non-pollution index range, the low-pollution index range, the medium-pollution index range and the high-pollution index range of the dose of external exposure by air immersion;

[0043] Evaluating the dose of external exposure on the ground surface according to a preset second dose index to obtain the pollution level of the dose of external exposure on the ground surface, where the second dose index is used to indicate the non-pollution index range, the low-pollution index range, the medium-pollution index range and the high-pollution index range of the dose of external exposure on the ground surface;

[0044] Evaluate the dose of the inhaled internal irradiation according to a preset third dose index to obtain the pollution level of the dose of the inhaled internal irradiation, where the third dose index is used to indicate the pollution-free index range, low-pollution index range, medium-pollution index range, and high-pollution index range of the dose of the inhaled internal irradiation;

[0045] Take the dose of the airborne submersion external irradiation and the corresponding pollution level, the dose of the surface external irradiation and the corresponding pollution level, and the dose of the inhaled internal irradiation and the corresponding pollution level as the evaluation result.

[0046] In some embodiments, after taking the dose of the airborne submersion external irradiation and the corresponding pollution level, the dose of the surface external irradiation and the corresponding pollution level, and the dose of the inhaled internal irradiation and the corresponding pollution level as the evaluation result, the method further includes:

[0047] If at least one of the pollution levels of the dose of the airborne submersion external irradiation, the pollution level of the dose of the surface external irradiation, and the pollution level of the dose of the inhaled internal irradiation in the evaluation result reaches a preset high-pollution level, highlight the dose that reaches the high-pollution level.

[0048] To achieve the above object, a second aspect of the embodiments of the present application proposes an evaluation device for the impact of off-site radioactive material release in a nuclear power plant, and the device includes:

[0049] An acquisition module, configured to acquire an evaluation range for evaluating the impact of radioactive material release, where the evaluation range is determined according to the release location of the radioactive material, and the radioactive material is released in the form of a plume;

[0050] A simulation module, configured to simulate the generation and movement process of the plume in the evaluation range according to the meteorological conditions at the release location within a preset evaluation duration, to obtain the cumulative concentration and sedimentation concentration of the plume, where the cumulative concentration is obtained by accumulating the concentrations of the plume in the evaluation range during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles onto the two-dimensional plane of the evaluation range after sedimentation;

[0051] A calculation module, configured to calculate according to the cumulative concentration and the sedimentation concentration to obtain the dose of the airborne submersion external irradiation, the dose of the surface external irradiation, and the dose of the inhaled internal irradiation in the evaluation range;

[0052] An evaluation module, configured to perform a radiation evaluation according to the dose of the airborne submersion external irradiation, the dose of the surface external irradiation, and the dose of the inhaled internal irradiation to obtain an evaluation result.

[0053] The evaluation method and device for the impact of off-site radioactive material release in a nuclear power plant determine the evaluation range for assessing the impact of radioactive material release based on the release location of the radioactive material, and the radioactive material is released in the form of a plume. Then, within a preset evaluation duration, the generation and movement process of the plume are simulated within the evaluation range according to the meteorological conditions at the release location to obtain the cumulative concentration and sedimentation concentration of the plume. The cumulative concentration is obtained by accumulating the concentration in the evaluation range by the plume within the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles onto the two-dimensional plane of the evaluation range after sedimentation. By calculating based on the cumulative concentration and sedimentation concentration, the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation in the evaluation range can be obtained. Finally, radiation assessment is performed based on the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation to obtain the evaluation result. This application can solve the problem in the prior art that the accuracy of the evaluation of the impact of off-site radioactive material release in a nuclear power plant is relatively low due to the influence of meteorological condition changes. Description of the Drawings

[0054] Figure 1 is a schematic flowchart of the evaluation method for the impact of off-site radioactive material release in an embodiment of this application;

[0055] Figure 2 is a schematic diagram of grid division of the evaluation method for the impact of off-site radioactive material release in an embodiment of this application;

[0056] Figure 3 is a schematic diagram of plume generation and diffusion of the evaluation method for the impact of off-site radioactive material release in an embodiment of this application;

[0057] Figure 4 is a schematic diagram of plume area division of the evaluation method for the impact of off-site radioactive material release in an embodiment of this application;

[0058] Figure 5 is a schematic diagram of plume migration of the evaluation method for the impact of off-site radioactive material release in an embodiment of this application;

[0059] Figure 6 is a flowchart of plume consequence calculation for real-time changing meteorological conditions off-site of a nuclear power plant in an embodiment of this application;

[0060] Figure 7 is a schematic structural diagram of the evaluation device for the impact of off-site radioactive material release in an embodiment of this application. Detailed Embodiments

[0061] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0062] It should be noted that although functional modules are divided in the device schematic diagram and the logical sequence is shown in the flowchart, in some cases, the steps shown or described may be executed in a different module division in the device or a different sequence in the flowchart. Terms such as "first" and "second" in the description, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0064] After an accident occurs in a nuclear power plant, radioactive substances may be released from the containment to the environment along with core damage. After the radioactive substances are released outside the nuclear power plant, they will migrate, diffuse and settle under the influence of the off-site atmosphere, which will affect the real-time concentration distribution of radioactive substances outside the nuclear power plant. In the event of an accident, it is crucial to timely and correctly evaluate the off-site diffusion of pollutants and the radiation dose consequence distribution field in the time and space dimensions, accurately grasp the development of the accident consequences, so as to guide the public response and rescue actions after off-site emergency decision-making, give the best solutions for the evacuation routes of the public and the entry routes of the rescue teams, and minimize the impact of radioactive substances on the off-site public and rescue personnel, which is of great importance for restricting the deterioration of radioactive accidents and ensuring economic and public safety.

[0065] When radioactive substances in a nuclear power plant are released into the atmosphere, they will migrate, diffuse and settle outside the site in the form of a plume. Under the influence of different off-site meteorological conditions, the plume carrying radioactive substances affects the areas passed by. On the one hand, the suspended radioactive substances in the plume will cause external radiation to the people on the ground and internal radiation after inhalation. On the other hand, the suspended radioactive substances in the plume will undergo dry and wet deposition on the ground, and the radioactive substances remaining on the ground will cause external radiation to the people in the area. Therefore, the coupled action of meteorological conditions, plume behavior and radioactive substance behavior will affect the dose in different regions and ultimately determine the off-site radioactive consequences. At present, most of the nuclear power plant off-site real-time radioactive consequence evaluation and nuclear emergency response systems adopt the classical Gaussian plume model, which cannot adapt to the real-time changing meteorological conditions, resulting in deviations between the evaluation results and the actual diffusion situation of radioactive substances.

[0066] Based on this, the embodiments of the present application provide a method and device for evaluating the impact of off-site radioactive material release from nuclear power plants, aiming to solve the problem in the prior art that the evaluation of the impact of off-site radioactive material release from nuclear power plants cannot adapt to real-time changing meteorological conditions. The embodiments of the present application analyze the segments of the plume released off-site, and combine with the three-dimensional grid division technology to track the migration, settlement, and diffusion of the radioactive plume in different off-site regions. At the same time, the impacts of atmospheric radioactive materials and sedimentary radioactive materials in the three-dimensional grids of different off-site regions are also coupled to calculate the dose of each three-dimensional grid region, thus providing more accurate and real-time support for the evaluation of the impact of radioactive release from nuclear power plants and nuclear emergency response.

[0067] The method and device for evaluating the impact of off-site radioactive material release from nuclear power plants provided by the embodiments of the present application will be specifically described through the following embodiments. First, the method for evaluating the impact of off-site radioactive material release from nuclear power plants in the embodiments of the present application will be described.

[0068] The method for evaluating the impact of off-site radioactive material release from nuclear power plants provided by the embodiments of the present application relates to the field of nuclear power technology. The method for evaluating the impact of off-site radioactive material release from nuclear power plants provided by the embodiments of the present application can be applied to a terminal, or to a server, or can also be software running on a terminal or a server. In some embodiments, the terminal can be a smart phone, a tablet computer, a notebook computer, a desktop computer, etc.; the server can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers, or can also be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements the method for evaluating the impact of off-site radioactive material release from nuclear power plants, etc., but is not limited to the above forms.

[0069] The present application can be used in many general-purpose or special-purpose computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multi-processor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0070] It should be noted that in each specific embodiment of the present application, when it comes to relevant processing based on data related to the user's identity or characteristics, such as user information, user behavior data, user historical data, and user location information, the user's permission or consent will be obtained first. Moreover, the collection, use, and processing of these data will comply with relevant laws, regulations, and standards. In addition, when the embodiments of the present application need to obtain the user's sensitive personal information, the user's separate permission or separate consent will be obtained through methods such as pop-up windows or redirecting to a confirmation page. After clearly obtaining the user's separate permission or separate consent, the necessary user-related data for the normal operation of the embodiments of the present application will be obtained.

[0071] Figure 1 It is a flowchart of an evaluation method for the impact of off-site radioactive material release in the nuclear power plant provided by the embodiments of the present application. Figure 1 The method in [description] may include, but is not limited to, steps S100 to S400.

[0072] Step S100, obtain the evaluation range for evaluating the impact of radioactive material release, where the evaluation range is determined according to the release location of the radioactive material, and the radioactive material is released in the form of a plume.

[0073] First, obtain the preset evaluation range for evaluating the impact of radioactive material release. The evaluation range is determined according to the release location of the radioactive material (usually a nuclear power plant). Taking the release location of the radioactive material as the center, determine the evaluation distances in the four directions of east, west, south, and north, such as 10 kilometers.

[0074] In this embodiment, the radioactive material is released in the form of a plume. A plume refers to a plume-shaped smoke body released by radioactive material into the atmosphere, usually in a long strip shape, and its shape and size depend on factors such as the height of the release source, meteorological conditions, and release rate. The plume will move and disperse with the change of wind direction and wind speed, affecting the surrounding area; and the radioactive material in the plume will be deposited on the ground surface through dry deposition and wet deposition, etc., causing surface pollution.

[0075] Step S200, within the preset evaluation duration, simulate the generation and movement process of the plume within the evaluation range according to the meteorological conditions at the release location, to obtain the cumulative concentration and sedimentation concentration of the plume. The cumulative concentration is the concentration obtained by accumulating the concentration of the plume in the evaluation range during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles on the two-dimensional plane of the evaluation range after sedimentation.

[0076] Within a preset evaluation duration, simulate the generation and movement process of the plume according to the meteorological conditions (wind speed, wind direction, atmospheric stability, rainfall, etc.) around the nuclear power plant. The generation and movement process of the plume includes the shape and concentration distribution of the newly released plume, as well as the migration trajectory and diffusion of the already generated plume, which can be represented by the cumulative concentration, i.e., the time-integrated concentration. The time-integrated concentration refers to the time integral of the air radioactive activity concentration within a given period. If the distribution over time is uniform, it is the product of the air radioactive activity concentration and time, with the unit of Bq·s / m 3 In addition, the effects of dry deposition and wet deposition on the plume should be considered, and the deposition amount of radioactive substances in the plume should be calculated, which can be represented by the deposition concentration. The deposition concentration refers to the concentration of the plume that settles onto a two-dimensional plane after deposition, with the unit of Bq / m 2 .

[0077] Step S300, calculate according to the cumulative concentration and the deposition concentration to obtain the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation within the evaluation range.

[0078] In this embodiment, external exposure by air immersion refers to the radiation caused by atmospheric pollutants near the ground surface to the public. The dose of external exposure by air immersion can be calculated through the cumulative concentration, the conversion factor of the air immersion exposure dose rate, and the shielding factor.

[0079] In this embodiment, external exposure on the ground surface is the radiation caused by radioactive substances adhering to the ground surface due to various deposition effects; the dose of external exposure on the ground surface can be calculated through the deposition concentration, the conversion factor of the external exposure dose rate on the ground surface, and the shielding factor.

[0080] In this embodiment, internal exposure by inhalation refers to the radiation exposure to the internal organs of the human body when radioactive substances are inhaled by the human body in gaseous or solid form and enter the human body; the dose of internal exposure by inhalation can be calculated through the cumulative concentration, the conversion factor of the internal exposure dose rate by inhalation, and the breathing rate.

[0081] Step S400, conduct a radiation assessment based on the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation to obtain an assessment result.

[0082] In this embodiment, conduct a radiation assessment on the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation respectively, and obtain the pollution levels of external exposure by air immersion, external exposure on the ground surface, and internal exposure by inhalation, and use the obtained pollution levels as the assessment result.

[0083] This embodiment takes into account the real-time changing meteorological conditions and conducts simulations based on the meteorological conditions at the release site and the radioactive material release conditions, enabling more accurate simulation of the generation, movement, and settlement processes of the radioactive plume, thereby obtaining more reliable evaluation results. At the same time, it considers three types of radiation, namely external exposure by air immersion, external exposure on the ground surface, and internal exposure by inhalation, and can comprehensively evaluate the impact of radioactive substances on the environment and human health.

[0084] In some embodiments, step S200 may include but is not limited to steps S210 to S240:

[0085] Step S210, perform three-dimensional grid division on the evaluation scope to obtain a plurality of three-dimensional grids, and each of the three-dimensional grids corresponds to a three-dimensional space of the evaluation scope;

[0086] Step S220, the evaluation duration includes a plurality of time periods, and for each of the plurality of time periods, the following processing is performed in chronological order:

[0087] Step S230, there are a plurality of plumes. For any one of the plurality of plumes, simulate the generation and movement processes of the plume in the plurality of three-dimensional grids according to the meteorological conditions at the release site, and obtain the cumulative concentration and settlement concentration of the plume in the covered three-dimensional grids during the time period;

[0088] Step S240, accumulate the cumulative concentration and settlement concentration of the plume in the covered three-dimensional grids obtained in each time period respectively to obtain the cumulative concentration and settlement concentration of the plume.

[0089] In this embodiment, the evaluation scope is divided into a plurality of three-dimensional grids; the evaluation duration is divided into a plurality of time periods (characteristic time steps). According to the meteorological conditions of each time period, simulate the generation and diffusion processes of newly released plumes. Considering the influence of the wind field on the plume, simulate the migration and diffusion processes of the generated plumes.

[0090] Determine the grids in the plume coverage area, calculate the influence of the plume on each grid point during the migration process, and evaluate using the time-integrated concentration. The time-integrated concentration can measure the continuous impact of pollutants on a certain location.

[0091] The plume will have a settlement effect in the grid area it passes through. Some radioactive substances will remain on the ground surface due to the influence of dry deposition and wet deposition and continuously affect the dose calculation in the grid. In addition, the settlement phenomenon of radioactive substances will also affect the concentration of radioactive substances in the plume. Calculate the settlement concentration in the grids in the plume coverage area according to the meteorological conditions of each time period.

[0092] Obtain the cumulative concentration and sedimentation concentration of each grid in each time period, and for each grid, add the cumulative concentration and sedimentation concentration of each time period respectively to obtain the total cumulative concentration and total sedimentation concentration of each grid within the evaluation duration.

[0093] Specifically, in some embodiments, step S230 may include but is not limited to steps S231 to S234:

[0094] Step S231, within the time period, use a three-dimensional Gaussian distribution model to simulate the generation process of the plume in multiple three-dimensional grids to obtain the concentration distribution of the plume;

[0095] Step S232, within the time period, calculate the movement range of the plume to obtain the coverage area of the plume;

[0096] Step S233, according to the coverage area of the plume, determine the three-dimensional grids covered by the plume;

[0097] Step S234, the meteorological conditions include the wind speed at the release location during the time period, and calculate according to the wind speed during the time period and the concentration distribution of the plume to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period.

[0098] In this embodiment, a three-dimensional Gaussian distribution model is used to simulate the generation process of the plume. This model assumes that the plume concentration follows a Gaussian distribution in space, that is, the concentration decreases with the increase in the distance from the release point. Through the three-dimensional Gaussian distribution model, the concentration distribution of the plume in multiple three-dimensional grids can be obtained. Specifically, the concentration distribution can be calculated according to the radioactive substance release rate and the diffusion coefficients in the x, y, and z directions. The radioactive substance release rate can be obtained according to the actual situation, such as through real-time detection by an instrument, and the specific acquisition method is not limited here. The diffusion coefficients in the x, y, and z directions can be obtained using empirical formulas or models, or can be preset according to the actual situation, and are not limited here.

[0099] According to the wind speed and the diffusion characteristics of the plume, calculate the movement range of the plume in a specific time period. The movement range determines the area affected by the plume, that is, the coverage area of the plume. According to the coverage area of the plume, determine which three-dimensional grids are affected by the plume to obtain the three-dimensional grids covered by the plume. For each three-dimensional grid covered by the plume, calculate the cumulative concentration and sedimentation concentration of the plume in this grid according to the wind speed and the concentration distribution of the plume. The wind speed can be obtained according to the actual situation, such as through real-time detection by an instrument, and the specific acquisition method is not limited here.

[0100] Specifically, in some embodiments, step S233 may include but is not limited to the following steps:

[0101] Obtain the three-dimensional coordinates of any three-dimensional grid;

[0102] If the three-dimensional coordinates are within the coverage area of the plume, determine that the three-dimensional grid is a three-dimensional grid covered by the plume;

[0103] If the three-dimensional coordinates are not within the coverage area of the plume, determine whether the three-dimensional coordinates of the next three-dimensional grid are within the coverage area of the plume until all three-dimensional grids are traversed.

[0104] In this embodiment, obtain the coordinate information of all three-dimensional grids. Each grid has three coordinate values, which respectively represent its position in three-dimensional space. For each grid, determine whether its coordinates are within the coverage area of the plume; if the grid coordinates are within the coverage area, the grid is determined to be a three-dimensional grid covered by the plume; if the grid coordinates are not within the coverage area, continue to determine the coordinates of the next grid until all three-dimensional grids have been judged. Thus, all grids affected by the plume, that is, the three-dimensional grids covered by the plume, are identified.

[0105] Specifically, in some embodiments, step S234 may include but is not limited to the following steps:

[0106] Calculate according to the wind speed in the time period and the concentration distribution of the plume to obtain the cumulative concentration of the plume in the covered three-dimensional grid during the time period;

[0107] The settling concentration of the plume includes dry settling concentration and wet settling concentration. Calculate according to the wind speed in the time period, the concentration distribution of the plume and the dry deposition rate to obtain the dry settling concentration of the plume in the covered three-dimensional grid during the time period;

[0108] Calculate according to the wind speed in the time period, the concentration distribution of the plume and the scavenging coefficient to obtain the wet settling concentration of the plume in the covered three-dimensional grid during the time period;

[0109] Calculate according to the dry settling concentration and wet settling concentration of the plume in the covered three-dimensional grid during the time period to obtain the settling concentration of the plume in the covered three-dimensional grid during the time period.

[0110] In this embodiment, dry deposition and wet deposition are two main ways of radioactive substance deposition. Dry deposition refers to the direct deposition of radioactive substances from the atmosphere to the ground or other surfaces in the form of aerosols or particles without the participation of moisture. Dry deposition is mainly affected by factors such as gravity, electrostatic adsorption, collision, and turbulence. Radioactive substances move with the air current in the air. When they encounter obstacles (such as the ground, buildings, etc.) or their own gravity is large enough, they will settle down. Dry deposition will lead to an increase in the concentration of radioactive substances on the ground surface, thus increasing the external exposure dose on the ground surface. In addition, the radioactive substances deposited by dry deposition may also be inhaled by animals or humans, causing internal exposure. Wet deposition refers to the deposition of radioactive substances from the atmosphere to the ground or other surfaces in the form of precipitation (such as rain, snow, fog, etc.). Wet deposition is mainly affected by factors such as precipitation intensity, precipitation type, and the concentration of radioactive substances in the cloud. Radioactive substances combine with water droplets and settle to the ground along with the precipitation. Wet deposition will lead to an increase in the concentration of radioactive substances in the ground surface and soil, thus increasing the external exposure dose on the ground surface. In addition, the radioactive substances deposited by wet deposition may also be absorbed by plants, enter the food chain, and ultimately affect human health.

[0111] In each time period, for each covered three-dimensional grid, according to the concentration distribution and wind speed of the plume, calculate the cumulative concentration of the plume in this grid; according to the concentration distribution, wind speed and dry deposition rate of the plume, calculate the dry deposition concentration of the plume in this grid, and the dry deposition rate can be a preset value; according to the concentration distribution, wind speed and scavenging coefficient of the plume, calculate the wet deposition concentration of the plume in this grid, and the scavenging coefficient can be a preset value; add the dry deposition concentration and the wet deposition concentration to obtain the total deposition concentration of this grid.

[0112] Specifically, in some embodiments, step S240 may include but is not limited to steps S241 to S243:

[0113] Step S241, according to the coordinates of the three-dimensional grid covered by the plume, obtain the cumulative concentration of the plume in this three-dimensional grid in each time period and the deposition concentration of the plume in this three-dimensional grid in each time period;

[0114] Step S242, accumulate the cumulative concentrations in each time period in each three-dimensional grid covered by each plume to obtain the cumulative concentration of the plume;

[0115] Step S243, accumulate the deposition concentrations in each time period in each three-dimensional grid covered by each plume to obtain the deposition concentration of the plume.

[0116] In this embodiment, by traversing the influence of each plume on each three-dimensional grid in each time period within the evaluation duration, the cumulative concentration and sedimentation concentration of each grid after the end of the evaluation duration, as well as the influence range of each plume, can be calculated, thereby evaluating the pollution degree of radioactive substances.

[0117] Specifically, first, the off-site evaluation range of the nuclear power plant is divided into multiple three-dimensional grids, and each grid represents a spatial region. Assuming the nuclear power plant as the center of calculation, the radioactive consequences at distances D in the four directions of east, west, south, and north outside the plant are evaluated. eval within. As Figure 2 shown, assuming each grid is square with a size of d grid ×d grid , where d grid is the side length of the square grid, then the number of grids is:

[0118]

[0119] The regional grid is the basis for off-site radioactive consequence evaluation. Based on this, research on plume generation, diffusion, etc. will be carried out, and the influence of the plume on different grids will be traced, so as to obtain the change of radioactive dose in different time and space dimensions.

[0120] Secondly, the entire evaluation duration is divided into multiple time periods, such as every minute, every 10 minutes, etc. Within each time period, plume simulation is carried out according to the meteorological conditions at that time (wind speed, wind direction, atmospheric stability, etc.).

[0121] Then, as Figure 3 shown, under the condition of changing meteorological conditions, assuming that the gas phase conditions remain unchanged within each characteristic time (i.e., each time period), then the wind speed remains unchanged during this period, and the newly released plume is in a long strip shape. Taking the i-th characteristic time step, the axial length of the newly generated plume within this characteristic time step is:

[0122] L axis,i = dt i ·u i ;

[0123] where dt i is the length of this characteristic time step, s; u i is the wind speed within this characteristic time step, m / s.

[0124] In this embodiment, it is assumed that the released long plume diffuses in the x, y, and z directions, and the diffusion coefficients σ x , σ y , σ zBoth increase with the accumulation of the trajectory length. The concentration distribution of the newly released plume is equivalent to the time integral of a release point generating a three-dimensional Gaussian plume translated from the origin to the downwind distance L axis,i where the diffusion parameters increase with the trajectory during this process.

[0125] Assuming that the radioactive substances released from the release point follow a spherical three-dimensional Gaussian distribution, its concentration is:

[0126]

[0127] where QR i is the release rate of radioactive substances, kg / s; σ x , σ y , σ z are the diffusion coefficients in three directions, m.

[0128] Assuming that the wind direction is the same as the x direction, the concentration of a new plume released at the i-th characteristic time step is:

[0129]

[0130] where u i is the wind speed during this period, m / s; h is the relative height between the release point and the ground, m.

[0131] Expressing the concentration distribution of the newly generated plume in terms of the error function erf, we have:

[0132]

[0133] where the function error function

[0134] After the plume is released, it migrates under the action of the wind field. During the migration process, as the trajectory of the plume increases, the diffusion coefficient continuously increases, and the plume continuously changes, affecting the relevant area during the change process. Since the wind field is stable within each characteristic time step dt i the plume will move rigidly, that is, the plume axis moves parallel within this time. At the same time, due to the diffusion phenomenon of the plume, the influence range gradually becomes larger.

[0135] As Figure 4 shown, when considering a long plume, a region needs to be delimited for calculation, and then the lower limit of the calculation result is taken to give the behavior and influence of the plume. The plume is centered on the plume axis. In this method, the region on the horizontal plane of the plume is divided into rectangles, and y max is extended respectively in the y direction of the plume, and p fWith p b 。

[0136] The plume moves under the action of the wind field and diffuses during the movement, causing its size to continuously increase. The plume affects all the points passed through within a characteristic time step dt i and thus the points in the plume coverage area and the affected area need to be considered. The migration of a plume within a characteristic time step is shown Figure 5 as follows.

[0137] Finally, for the grid points in the plume migration affected area, it is necessary to couple and calculate the impact of the plume migration on this grid point. From the concentration distribution c i (x, y, z) of the plume, it can be seen that during the movement of the plume, the position of a grid relative to the plume is constantly changing and is a function of time, so its concentration is also constantly changing, which is related to the wind speed direction at each characteristic time dt i .

[0138] During the movement of the plume, in order to measure the continuous impact of pollutants on a certain point, the time-integrated concentration of this point can be used for evaluation. The time-integrated concentration of a plume released within the i-th characteristic time step at the j-th characteristic time step is:

[0139]

[0140] where, TIC i,j (x, y, z) is the time-integrated concentration of the plume released within the i-th characteristic time step at the j-th characteristic time step, Bq·s / m 3 ; T j-1 is the sum of the characteristic time steps, c i (x, y, z) is the concentration of the plume released within the i-th characteristic time step at (x, y, z), Bq / m 3 ; u x and u y are the wind speeds in the x and y directions of the plume at this moment, m / s.

[0141] Since the plume will undergo a sedimentation effect in the grid area it passes through, some radioactive substances will be retained on the ground surface due to the influence of dry and wet deposition and continuously affect the dose calculation within this grid. In addition, the sedimentation phenomenon of radioactive substances will also affect the concentration of radioactive substances in the plume.

[0142] The surface concentration of dry deposition is:

[0143]

[0144] Among them, Cd i,j (x,y) is the dry deposition concentration of the plume released at the i-th characteristic time step at the grid (x,y) at the j-th characteristic time step, Bq / m 2 ; T j-1 is the sum of characteristic time steps, v i (x,y,z) is the concentration of the plume released at the i-th characteristic time step at (x,y,z), Bq / m 3 ; v d is the dry deposition rate, m / s.

[0145] The total dry deposition concentration at the grid (x,y) at the j-th characteristic time step is:

[0146] Cd j (x,y) = ∑ i Cd i,j (x,y);

[0147] In this embodiment, it is assumed that after dry deposition occurs, the total amount of radioactive substances in each plume will decrease accordingly, and the relative distribution within the plume remains unchanged. Thus, the sedimentation amount of the plume released at the i-th characteristic time step at the grid (x,y) at the j-th characteristic time step is:

[0148]

[0149] Among them, d grid is the side length of the square grid, m.

[0150] The wet deposition concentration is:

[0151]

[0152] Among them, Cw i,j (x,y) is the wet deposition concentration of the plume released at the i-th characteristic time step at the grid (x,y) at the j-th characteristic time step, Bq / m 2 ; T j-1 is the sum of characteristic time steps, c i (x,y,z) is the concentration of the plume released at the i-th characteristic time step at (x,y,z), Bq / m 3 ; Λ is the scavenging coefficient, / s.

[0153] The total wet deposition concentration at the grid (x,y) at the j-th characteristic time step is:

[0154] Cw j (x,y) = ∑ i Cw i,j (x,y);

[0155] Similarly, the sedimentation amount of the plume released within the i-th characteristic time step at the grid (x, y) at the j-th characteristic time step is:

[0156]

[0157] Then, the total sedimentation concentration at the grid (x, y) at the j-th characteristic time step is:

[0158] Cg j (x,y) = Cd j (x,y) + Cw j (x,y);

[0159] The concentration of the plume released within the i-th characteristic time step at the (j + 1)-th characteristic time step:

[0160]

[0161] where Q i,0 is the total amount of the initial radioactive substance of the plume released within the i-th characteristic time step, in Bq.

[0162] In this embodiment, by evaluating the plume in each time period, the radioactive dose distribution in different regions can be calculated in real time; dividing the evaluation range into three-dimensional grids can more accurately simulate the diffusion of the plume in three-dimensional space and calculate the radioactive dose in each grid; by tracking the generation, migration, and diffusion processes of multiple plumes and evaluating the influence of each plume, coordinating the plume tracking with the regional grid can more comprehensively evaluate the impact of radioactive substances on the entire region; and considering the effects of dry deposition and wet deposition on radioactive substances can more comprehensively evaluate the radioactive consequences.

[0163] In some embodiments, step S300 may include but is not limited to steps S310 to S330:

[0164] Step S310, calculate according to the shielding factor, the air immersion exposure dose rate conversion factor, the cumulative concentration and sedimentation concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of external exposure to air immersion in the three-dimensional grid covered by the plume during the time period;

[0165] Step S320, calculate according to the shielding factor, the surface external exposure dose rate conversion factor, the cumulative concentration and sedimentation concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of external exposure to the surface in the three-dimensional grid covered by the plume during the time period;

[0166] Step S330: Calculate based on the breathing rate, the inhalation internal exposure dose rate conversion factor, the cumulative concentration and the deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period, to obtain the dose of inhalation internal exposure in the three-dimensional grid covered by the plume during the time period.

[0167] In nuclear accident emergency response, it is often necessary to evaluate the impact of radioactive substances on public health, and the most important indicator is the radioactive dose. The radioactive dose can cause harm to the human body in different ways, mainly including: air submersion external exposure, ground surface external exposure and inhalation internal exposure. The dose conversion factor is a parameter for converting radiation energy to dose. The values of the air submersion exposure dose rate conversion factor, the ground surface external exposure dose rate conversion factor, and the inhalation internal exposure dose rate conversion factor can be preset according to the actual situation and are not limited here. The shielding factor is a parameter used to measure the radiation interception ability of shielding materials, usually used to measure the shielding effect of a certain material on electromagnetic radiation. The shielding factor can be set according to the actual situation. Exemplarily, if there are shielding substances (such as houses, protective clothing, etc.) at the location, the value of the shielding factor can be set according to the shielding effect of the shielding substance. The value of the breathing rate can be set according to the breathing rate of normal adults or can be preset according to the actual situation and is not limited here.

[0168] Specifically, based on the cumulative concentration (time-integrated concentration) and the deposition concentration (ground surface concentration) of each point, the air submersion external exposure, the ground surface external exposure and the inhalation internal exposure at that point can be calculated.

[0169] Air submersion exposure is the radiation caused by atmospheric pollutants near the ground surface to the public. The air submersion external exposure caused by the plume is:

[0170] D AS (x,y) = ∑ i,j TIC i,j (x,y,0)·DC AS ·SF AS ;

[0171] Where, D AS (x,y) is the air submersion external exposure dose of the grid (x,y), Sv; TIC i,j (x,y,z) is the time-integrated concentration of the plume released in the i-th characteristic time step in the j-th characteristic time step, Bq·s / m 3 ; DC AS is the air submersion exposure dose rate conversion factor, Sv / (Bq·s / m 3 ); SF AS is the shielding factor, dimensionless.

[0172] External surface irradiation is the radiation caused by radioactive substances adhering to the surface due to various deposition effects. The external surface irradiation is as follows:

[0173] D GS (x,y) = [∑ i Cg i (x,y)dt i ·DC GS ·SF GS ;

[0174] Among them, D GS (x,y) is the external surface irradiation dose of the grid (x,y), Sv; Cg i (x,y) is the surface concentration of the grid (x,y) in the i-th characteristic time step, Bq / m 2 ; DC GS is the external surface irradiation dose rate conversion factor, Sv / (Bq·s / m 2 ); SF GS is the shielding factor, dimensionless.

[0175] Inhalation internal irradiation is the radiation generated inside the human body when humans inhale gases containing pollutants during breathing. The inhalation internal irradiation is as follows:

[0176] D INH (x,y) = ∑ i,j TIC i,j (x,y,0)·DC INH ·BR;

[0177] Among them, D INH (x,y) is the inhalation internal irradiation dose of the grid (x,y), Sv; TIC i,j (x,y,z) is the time-integrated concentration of the plume released in the i-th characteristic time step in the j-th characteristic time step, Bq·s / m 3 ; DC INH is the inhalation internal irradiation dose rate conversion factor, Sv / Bq; BR is the breathing rate, m 3 / s.

[0178] In this embodiment, by calculating different types of irradiation doses, the harm of radioactive substances to public health can be more comprehensively evaluated, and more accurate information can be provided for nuclear emergency response, so as to better protect the health and safety of the public.

[0179] In some embodiments, step S400 may include but is not limited to steps S410 to S440:

[0180] Step S410: Evaluate the dose of the air submersion external irradiation according to a preset first dose index to obtain the pollution level of the dose of the air submersion external irradiation. The first dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and heavy pollution index range of the dose of the air submersion external irradiation:

[0181] Step S420: Evaluate the dose of the surface external irradiation according to a preset second dose index to obtain the pollution level of the dose of the surface external irradiation. The second dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and heavy pollution index range of the dose of the surface external irradiation;

[0182] Step S430: Evaluate the dose of the surface external irradiation according to a preset second dose index to obtain the pollution level of the dose of the surface external irradiation. The second dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and heavy pollution index range of the dose of the surface external irradiation;

[0183] Step S440: Take the dose of the air submersion external irradiation and the corresponding pollution level, the dose of the surface external irradiation and the corresponding pollution level, and the dose of the inhalation internal irradiation and the corresponding pollution level as the evaluation result.

[0184] In this embodiment, three doses are evaluated respectively, and corresponding pollution level indexes are preset for each dose, specifically including: using the first dose index to divide the air submersion external irradiation dose into four levels: non-pollution, low pollution, medium pollution, and heavy pollution; using the second dose index to divide the surface external irradiation dose into four levels: non-pollution, low pollution, medium pollution, and heavy pollution; using the third dose index to divide the inhalation internal irradiation dose into four levels: non-pollution, low pollution, medium pollution, and heavy pollution. The non-pollution level means the dose is lower than the non-pollution index range; the low pollution level means the dose is between the non-pollution index range and the low pollution index range; the medium pollution level means the dose is between the low pollution index range and the medium pollution index range; the heavy pollution level means the dose is higher than the heavy pollution index range. Exemplarily, the first dose index is as follows: non-pollution: 0 - 1 mSv; low pollution: 1 - 10 mSv; medium pollution: 10 - 100 mSv; heavy pollution: > 100 mSv. The specific dose index can be set according to the actual situation and is not limited herein.

[0185] The pollution level can guide the public to take corresponding protective measures. For example, in a pollution-free area, the public can carry out normal activities without taking special protective measures; in a lightly polluted area, the public needs to take some simple protective measures, such as wearing masks and avoiding contact with contaminated objects; in a moderately polluted area, the public needs to take more stringent protective measures, such as wearing protective clothing and avoiding going out; in a heavily polluted area, the public needs to evacuate the area immediately and take comprehensive protective measures.

[0186] In this embodiment, by comparing the doses of air submersion external irradiation, ground surface external irradiation, and inhalation internal irradiation with the preset dose indexes, the harm degree caused by different radiation types to the human body can be evaluated; converting the dose values into pollution levels makes the evaluation results more intuitive and understandable; the pollution level can quickly identify the polluted areas, facilitating risk management and emergency response.

[0187] In some embodiments, after step S400, it may further include but is not limited to step S500:

[0188] Step S500, if at least one of the pollution levels of the dose of air submersion external irradiation, the pollution level of the dose of ground surface external irradiation, and the pollution level of the dose of inhalation internal irradiation in the evaluation result reaches the preset severe pollution level, then highlight the dose that reaches the severe pollution level.

[0189] In this embodiment, if at least one of air submersion external irradiation, ground surface external irradiation, and inhalation internal irradiation reaches the severe pollution level, then highlight the dose of this item to remind relevant personnel to take emergency protective measures.

[0190] In this embodiment, by highlighting the dose that reaches the severe pollution level, high-risk areas can be quickly identified, facilitating risk management and emergency response; it can also issue alarms according to the pollution level, take protective measures in a timely manner, and ensure the safety of the public.

[0191] In this embodiment, grids are divided within a given area, and the formation and diffusion of new plumes are calculated based on the meteorological conditions and radioactive substance release conditions within each characteristic time interval. At the same time, the migration trajectories and diffusion situations of the already generated plumes under the influence of these meteorological conditions will also be calculated, and based on this, the grids corresponding to their influence areas will be determined. For the grids within the influence area, on the premise of coupling the phenomena of dry deposition and wet deposition, calculate the radioactive substance concentration and time-integrated concentration of the plume, and based on this, calculate the external irradiation and internal irradiation doses received by the population within the grid. The calculation process is as Figure 6 shown.

[0192] In the embodiment of the present application, by determining the evaluation range of the release of radioactive substances, simulating the generation and movement process of the radioactive substances released in the form of a plume within the evaluation range under specific meteorological conditions, the cumulative concentration and the sedimentation concentration are calculated. Based on the cumulative concentration and the sedimentation concentration, the air submersion external exposure dose, the ground surface external exposure dose, and the inhalation internal exposure dose are further calculated, so as to perform radiation evaluation and obtain the evaluation result. By means of plume tracking and regional grid coordination, the release, migration, and sedimentation of the plume are synchronously coupled, and the dose consequences caused by the radioactive substances in different off-site regional grids are calculated, ensuring the integrity of the whole process. In the embodiment of the present application, plume tracking and regional grid coordination are carried out simultaneously by means of grid division and time segmentation; the concentration of each plume is calculated considering time segmentation; the influence of the moving plume on the determined grid is described by means of time-integrated concentration; the radioactive substance sedimentation mechanism is dynamically coupled during the migration process, and the concentration or total amount of the radioactive substances in each plume and grid can be dynamically calculated, realizing the tracking calculation of the plume behavior and the dose of the affected area under changing meteorological conditions, and performing real-time evaluation of the off-site radioactive consequences; moreover, the calculated real-time dose distribution can provide support for the evaluation of the radioactive release consequences of nuclear power plants and nuclear emergency response.

[0193] Please refer to Figure 7 , the embodiment of the present application further provides an evaluation device 700 for the influence of off-site radioactive substance release of a nuclear power plant, which can implement the above-mentioned evaluation method for the influence of off-site radioactive substance release of a nuclear power plant. The device includes:

[0194] An acquisition module 10, configured to acquire an evaluation range for evaluating the influence of the release of radioactive substances, where the evaluation range is determined according to the release location of the radioactive substances, and the radioactive substances are released in the form of a plume;

[0195] A simulation module 20, configured to simulate the generation and movement process of the plume within the evaluation range according to the meteorological conditions at the release location within a preset evaluation duration, and obtain the cumulative concentration and the sedimentation concentration of the plume. The cumulative concentration is obtained by accumulating the concentration of the plume in the evaluation range during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles on the two-dimensional plane of the evaluation range after sedimentation;

[0196] A calculation module 30, configured to calculate according to the cumulative concentration and the sedimentation concentration to obtain the dose of air submersion external exposure, the dose of ground surface external exposure, and the dose of inhalation internal exposure of the evaluation range;

[0197] An evaluation module 40, configured to perform radiation evaluation according to the dose of air submersion external exposure, the dose of ground surface external exposure, and the dose of inhalation internal exposure to obtain an evaluation result.

[0198] In some embodiments, the simulation module 20 may include:

[0199] A sub-module for dividing the evaluation range into three-dimensional grids to obtain a plurality of three-dimensional grids, and each three-dimensional grid corresponds to a three-dimensional space of the evaluation range;

[0200] A processing sub-module, where the evaluation duration includes a plurality of time periods, and for each of the plurality of time periods, the following processing is performed in chronological order:

[0201] A simulation sub-module, where the number of the plumes is multiple, and for any one of the multiple plumes, the generation and movement processes of the plume are simulated in a plurality of three-dimensional grids according to the meteorological conditions at the release location, and the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period are obtained;

[0202] An accumulation sub-module for respectively accumulating the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids obtained in each time period to obtain the cumulative concentration and sedimentation concentration of the plume.

[0203] In some embodiments, the simulation sub-module may include:

[0204] A perturbation unit for simulating the generation process of the plume in a plurality of three-dimensional grids using a three-dimensional Gaussian distribution model during the time period to obtain the concentration distribution of the plume;

[0205] A first calculation unit for calculating the movement range of the plume during the time period to obtain the covered area of the plume;

[0206] A determination unit for determining the three-dimensional grids covered by the plume according to the covered area of the plume;

[0207] A second calculation unit, where the meteorological conditions include the wind speed at the release location during the time period, and calculates the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period according to the wind speed during the time period and the concentration distribution of the plume.

[0208] In some embodiments, the determination unit may include:

[0209] An acquisition sub-unit for acquiring the three-dimensional coordinates of any one three-dimensional grid;

[0210] A determination sub-unit for determining that the three-dimensional grid is the three-dimensional grid covered by the plume if the three-dimensional coordinates are located in the covered area of the plume;

[0211] A determination subunit, configured to, if the three-dimensional coordinates do not lie within the coverage area of the plume, determine whether the three-dimensional coordinates of the next three-dimensional grid lie within the coverage area of the plume until all three-dimensional grids are traversed.

[0212] In some embodiments, the second calculation unit may include:

[0213] An accumulated concentration calculation subunit, configured to calculate based on the wind speed during the time period and the concentration distribution of the plume to obtain the accumulated concentration of the plume in the covered three-dimensional grids during the time period;

[0214] A dry deposition concentration calculation subunit, where the deposition concentration of the plume includes a dry deposition concentration and a wet deposition concentration, and is configured to calculate based on the wind speed during the time period, the concentration distribution of the plume, and the dry deposition rate to obtain the dry deposition concentration of the plume in the covered three-dimensional grids during the time period;

[0215] A wet deposition concentration calculation subunit, configured to calculate based on the wind speed during the time period, the concentration distribution of the plume, and the scavenging coefficient to obtain the wet deposition concentration of the plume in the covered three-dimensional grids during the time period;

[0216] A deposition concentration calculation subunit, configured to calculate based on the dry deposition concentration and the wet deposition concentration of the plume in the covered three-dimensional grids during the time period to obtain the deposition concentration of the plume in the covered three-dimensional grids during the time period.

[0217] In some embodiments, the calculation module 30 may include:

[0218] An air immersion external exposure dose calculation sub-module, configured to calculate based on the shielding factor, the air immersion exposure dose rate conversion factor, the accumulated concentration and the deposition concentration of the plume in the three-dimensional grids covered by the plume during the time period to obtain the dose of air immersion external exposure in the three-dimensional grids covered by the plume during the time period;

[0219] A surface external exposure dose calculation sub-module, configured to calculate based on the shielding factor, the surface external exposure dose rate conversion factor, the accumulated concentration and the deposition concentration of the plume in the three-dimensional grids covered by the plume during the time period to obtain the dose of surface external exposure in the three-dimensional grids covered by the plume during the time period;

[0220] An inhalation internal exposure dose calculation sub-module, configured to calculate based on the breathing rate, the inhalation internal exposure dose rate conversion factor, the accumulated concentration and the deposition concentration of the plume in the three-dimensional grids covered by the plume during the time period to obtain the dose of inhalation internal exposure in the three-dimensional grids covered by the plume during the time period.

[0221] In some embodiments, the accumulation sub-module may include:

[0222] An acquisition unit, configured to obtain the cumulative concentration of the plume in each time period of the three-dimensional grid covered by the plume and the sedimentation concentration of the plume in the three-dimensional grid in each time period according to the coordinates of the three-dimensional grid covered by the plume;

[0223] A first accumulation unit, configured to accumulate the cumulative concentrations in each time period of each three-dimensional grid covered by each plume to obtain the cumulative concentration of the plume;

[0224] A second accumulation unit, configured to accumulate the sedimentation concentrations in each time period of each three-dimensional grid covered by each plume to obtain the sedimentation concentration of the plume.

[0225] In some embodiments, the evaluation module 40 may include:

[0226] A first evaluation sub-module, configured to evaluate the dose of the external exposure by air immersion according to a preset first dose index, and obtain the pollution level of the dose of the external exposure by air immersion, where the first dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and high pollution index range of the dose of the external exposure by air immersion;

[0227] A second evaluation sub-module, configured to evaluate the dose of the external exposure on the ground surface according to a preset second dose index, and obtain the pollution level of the dose of the external exposure on the ground surface, where the second dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and high pollution index range of the dose of the external exposure on the ground surface;

[0228] A third evaluation sub-module, configured to evaluate the dose of the internal exposure by inhalation according to a preset third dose index, and obtain the pollution level of the dose of the internal exposure by inhalation, where the third dose index is used to indicate the non-pollution index range, low pollution index range, medium pollution index range, and high pollution index range of the dose of the internal exposure by inhalation;

[0229] An evaluation result generation sub-module, configured to use the dose of the external exposure by air immersion and the corresponding pollution level, the dose of the external exposure on the ground surface and the corresponding pollution level, and the dose of the internal exposure by inhalation and the corresponding pollution level as the evaluation result.

[0230] In some embodiments, the evaluation module 40 may further include:

[0231] A display sub-module, configured to highlight the dose that reaches the preset severe pollution level if at least one of the pollution levels of the dose of the air immersion external irradiation, the pollution level of the dose of the surface external irradiation, and the pollution level of the dose of the inhalation internal irradiation in the evaluation result reaches the preset severe pollution level.

[0232] The specific implementation manner of the evaluation device for the influence of the release of radioactive substances outside the nuclear power plant is basically the same as the specific embodiments of the above-mentioned evaluation method for the influence of the release of radioactive substances outside the nuclear power plant, and will not be elaborated herein.

[0233] The evaluation method for the influence of the release of radioactive substances outside the nuclear power plant and the evaluation device for the influence of the release of radioactive substances outside the nuclear power plant provided by the embodiments of the present application determine the evaluation range for evaluating the influence of the release of radioactive substances through the release location of the radioactive substances, and the radioactive substances are released in the form of a plume; then, within a preset evaluation duration, the generation and movement process of the plume is simulated within the evaluation range according to the meteorological conditions at the release location to obtain the cumulative concentration and the sedimentation concentration of the plume. The cumulative concentration is obtained by accumulating the concentration of the plume in the evaluation range during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles on the two-dimensional plane of the evaluation range after sedimentation; by calculating according to the cumulative concentration and the sedimentation concentration, the dose of the air immersion external irradiation, the dose of the surface external irradiation, and the dose of the inhalation internal irradiation of the evaluation range can be obtained; finally, a radiation evaluation is performed according to the dose of the air immersion external irradiation, the dose of the surface external irradiation, and the dose of the inhalation internal irradiation to obtain an evaluation result. The present application can solve the problem that the accuracy of the evaluation of the influence of the release of radioactive substances outside the nuclear power plant in the prior art is relatively low due to the influence of meteorological condition changes.

[0234] The embodiments described in the embodiments of the present application are for more clearly explaining the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0235] Those skilled in the art can understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than those shown in the figures, or combine some steps, or different steps.

[0236] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0237] Those of ordinary skill in the art will understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or a suitable combination thereof.

[0238] As used in the specification of this application and the above-mentioned drawings, the terms "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this application described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0239] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may mean: only A exists, only B exists, and both A and B exist at the same time. Here, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one)" or a similar expression thereof means any combination of these items, including any combination of single items (ones) or plural items (ones). For example, at least one (one) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0240] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the above-mentioned unit division is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of devices or units can be in electrical, mechanical, or other forms.

[0241] The units described above as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0242] In addition, the functional units in various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0243] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in various embodiments of the present application. The foregoing storage medium includes: USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs and other various media that can store programs.

[0244] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, and thus do not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. An assessment method for the impact of the release of radioactive substances outside the nuclear power plant, characterized in that, The method includes: Obtaining an evaluation range for evaluating the impact of the release of radioactive substances, where the evaluation range is determined according to the release location of the radioactive substances, and the radioactive substances are released in the form of a plume; Within a preset evaluation duration, simulating the generation and movement process of the plume within the evaluation range according to the meteorological conditions at the release location to obtain the cumulative concentration and sedimentation concentration of the plume. The cumulative concentration is obtained by accumulating the concentrations in the evaluation range by the plume during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles onto the two-dimensional plane of the evaluation range after sedimentation; Calculating based on the cumulative concentration and the sedimentation concentration to obtain the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation in the evaluation range; Performing a radiation assessment based on the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation to obtain an evaluation result.

2. The method according to claim 1, characterized in that, The evaluation duration includes multiple time periods; There are multiple plumes; The step of, within a preset evaluation duration, simulating the generation and movement process of the plume within the evaluation range according to the meteorological conditions at the release location to obtain the cumulative concentration and sedimentation concentration of the plume includes: Performing a three-dimensional grid division on the evaluation range to obtain a plurality of three-dimensional grids, and each three-dimensional grid corresponds to a three-dimensional space in the evaluation range; For each of the multiple time periods in chronological order, the following processing is performed: For any one of the multiple plumes, simulating the generation and movement process of the plume in the multiple three-dimensional grids according to the meteorological conditions at the release location to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period; Accumulating the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids obtained in each time period respectively to obtain the cumulative concentration and sedimentation concentration of the plume.

3. The method according to claim 2, wherein The meteorological conditions include the wind speed at the release location during the time period; The step of, for any one of the multiple plumes, simulating the generation and movement process of the plume in the multiple three-dimensional grids according to the meteorological conditions at the release location to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period includes: During the time period, using a three-dimensional Gaussian distribution model to simulate the generation process of the plume in the multiple three-dimensional grids to obtain the concentration distribution of the plume; During the time period, calculating the movement range of the plume to obtain the covered area of the plume; According to the covered area of the plume, determining the three-dimensional grids covered by the plume; Calculating based on the wind speed during the time period and the concentration distribution of the plume to obtain the cumulative concentration and sedimentation concentration of the plume in the covered three-dimensional grids during the time period.

4. The method according to claim 3, characterized in that, The step of, according to the covered area of the plume, determining the three-dimensional grids covered by the plume includes: Obtaining the three-dimensional coordinates of any one three-dimensional grid; If the three-dimensional coordinates are located in the covered area of the plume, determining the three-dimensional grid as the three-dimensional grid covered by the plume; If the three-dimensional coordinates are not located in the coverage area of the plume, determine whether the three-dimensional coordinates of the next three-dimensional grid are located in the coverage area of the plume until all three-dimensional grids are traversed.

5. The method according to claim 3, characterized in that, The deposition concentration of the plume includes dry deposition concentration and wet deposition concentration; The calculation of the cumulative concentration and deposition concentration of the plume in the covered three-dimensional grid during the time period according to the wind speed during the time period and the concentration distribution of the plume includes: Calculating the cumulative concentration of the plume in the covered three-dimensional grid during the time period according to the wind speed during the time period and the concentration distribution of the plume; Calculating the dry deposition concentration of the plume in the covered three-dimensional grid during the time period according to the wind speed during the time period, the concentration distribution of the plume, and the dry deposition rate; Calculating the wet deposition concentration of the plume in the covered three-dimensional grid during the time period according to the wind speed during the time period, the concentration distribution of the plume, and the scavenging coefficient; Calculating the deposition concentration of the plume in the covered three-dimensional grid during the time period according to the dry deposition concentration and wet deposition concentration of the plume in the covered three-dimensional grid during the time period.

6. The method according to claim 3, wherein The calculation of the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation in the evaluation range according to the cumulative concentration and the deposition concentration includes: Calculating the dose of external exposure by air immersion in the three-dimensional grid covered by the plume during the time period according to the shielding factor, the conversion factor of air immersion exposure dose rate, the cumulative concentration and deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period; Calculating the dose of external exposure on the ground surface in the three-dimensional grid covered by the plume during the time period according to the shielding factor, the conversion factor of external exposure dose rate on the ground surface, the cumulative concentration and deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period; Calculating the dose of internal exposure by inhalation in the three-dimensional grid covered by the plume during the time period according to the breathing rate, the conversion factor of internal exposure dose rate by inhalation, the cumulative concentration and deposition concentration of the plume in the three-dimensional grid covered by the plume during the time period.

7. The method according to claim 2, characterized in that, The cumulative addition of the cumulative concentration and deposition concentration of the plume in the covered three-dimensional grid obtained in each time period to obtain the cumulative concentration and deposition concentration of the plume includes: Obtaining the cumulative concentration of the plume in the three-dimensional grid in each time period and the deposition concentration of the plume in the three-dimensional grid in each time period according to the coordinates of the three-dimensional grid covered by the plume; Adding up the cumulative concentrations in each time period in each three-dimensional grid covered by the plume to obtain the cumulative concentration of the plume; Adding up the deposition concentrations in each time period in each three-dimensional grid covered by the plume to obtain the deposition concentration of the plume.

8. The method according to claim 6, characterized in that The radiation assessment according to the dose of external exposure by air immersion, the dose of external exposure on the ground surface, and the dose of internal exposure by inhalation to obtain an assessment result includes: Evaluate the dose of the external exposure by air immersion according to a preset first dose index to obtain the pollution level of the dose of the external exposure by air immersion, where the first dose index is used to indicate the non-pollution index range, low-pollution index range, medium-pollution index range, and high-pollution index range of the dose of the external exposure by air immersion; Evaluate the dose of the external exposure on the ground surface according to a preset second dose index to obtain the pollution level of the dose of the external exposure on the ground surface, where the second dose index is used to indicate the non-pollution index range, low-pollution index range, medium-pollution index range, and high-pollution index range of the dose of the external exposure on the ground surface; Evaluate the dose of the internal exposure by inhalation according to a preset third dose index to obtain the pollution level of the dose of the internal exposure by inhalation, where the third dose index is used to indicate the non-pollution index range, low-pollution index range, medium-pollution index range, and high-pollution index range of the dose of the internal exposure by inhalation; Take the dose of the external exposure by air immersion and the corresponding pollution level, the dose of the external exposure on the ground surface and the corresponding pollution level, and the dose of the internal exposure by inhalation and the corresponding pollution level as the evaluation result.

9. The method according to claim 8, characterized in that, After taking the dose of the external exposure by air immersion and the corresponding pollution level, the dose of the external exposure on the ground surface and the corresponding pollution level, and the dose of the internal exposure by inhalation and the corresponding pollution level as the evaluation result, the method further includes: If at least one of the pollution levels of the dose of the external exposure by air immersion, the pollution level of the dose of the external exposure on the ground surface, and the pollution level of the dose of the internal exposure by inhalation in the evaluation result reaches a preset high-pollution level, highlight the dose that reaches the high-pollution level.

10. An evaluation device for the impact of the release of radioactive substances outside a nuclear power plant, characterized in that, The device includes: An acquisition module, configured to acquire an evaluation range for evaluating the impact of the release of radioactive substances, where the evaluation range is determined according to the release location of the radioactive substances, and the radioactive substances are released in the form of a plume; A simulation module, configured to simulate the generation and movement process of the plume in the evaluation range according to the meteorological conditions at the release location within a preset evaluation duration to obtain the cumulative concentration and sedimentation concentration of the plume, where the cumulative concentration is obtained by accumulating the concentration of the plume in the evaluation range during the evaluation duration, and the sedimentation concentration refers to the concentration of the plume that settles onto the two-dimensional plane of the evaluation range after sedimentation; A calculation module, configured to calculate according to the cumulative concentration and the sedimentation concentration to obtain the dose of the external exposure by air immersion, the dose of the external exposure on the ground surface, and the dose of the internal exposure by inhalation in the evaluation range; An evaluation module, configured to perform a radiation evaluation according to the dose of the external exposure by air immersion, the dose of the external exposure on the ground surface, and the dose of the internal exposure by inhalation to obtain an evaluation result.

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