Method and system for evaluating off-site whole range radiation risk under severe accident of nuclear power plant

Abstract

The application provides a method and system for evaluating the whole range of radiation risk outside a nuclear power plant in a severe accident, and the method comprises the following steps: S1, a basic model architecture for evaluating the risk of radioactive accidents is built, the model requirements are adapted, and a corresponding basic database is established; S2, the characteristics of the radioactive plume after the accident are constructed; S3, the spatial gridding of the accident site and the discretization of the plume transmission are calculated; S4, the sampling meteorological conditions are obtained, and the plume transmission is simulated; S5, the radiation dose in the early stage of the grid domain is calculated, and the risk is evaluated; S6, the health effects in the early stage of the grid domain are evaluated; S7, the radiation dose in the medium and long term stage of the grid domain is calculated, and the dose risk is evaluated; S8, the health effect risk in the medium and long term stage is evaluated, and the consequences of the accident in the medium and long term stage are evaluated. The application simulates the whole transport process of the radioactive plume in a severe accident, considers the dry and wet deposition of the plume and the loss effects such as radioactive decay, and determines the activity of the radionuclide deposited on the ground and retained in the air within the spatial range outside the scene.

Description

Technical Field

[0001] This invention relates to the field of nuclear power radiation analysis, and in particular to a method and system for assessing the full-range radiation risk outside the nuclear power plant under severe accidents. Background Technology

[0002] Even under the strictest supervision, it is impossible to reduce the probability of a serious accident to zero in the operation of a nuclear power plant. Once a serious accident occurs, radioactive gaseous nuclides will leak instantaneously and rapidly condense into a plume in the atmosphere. Subsequently, propelled by wind fields, air pressure, and complex terrain, the plume can easily break through the site boundaries and spread to a wider area outside the site, causing persistent and irreversible radioactive contamination.

[0003] Given the long-term threat posed by radioactive materials to human health and the ecological environment, and from the perspective of ensuring public safety and sustainable environmental development, the state has formulated stringent radiation protection standards and regulatory requirements. The core objective is to ensure that radiation levels are consistently suppressed within a controllable and acceptable range under any operating conditions, especially in the event of a severe accident, to avoid irreversible damage to public health and the environment.

[0004] In the field of off-site radiation risk assessment, the main focus is on the radiation impact and potential consequences of radioactive materials on areas outside the nuclear power plant site boundary in the event of an accident or abnormal situation.

[0005] This impact and its consequences involve multiple levels:

[0006] First, regarding dose risk, the main focus is on the radiation dose received by the public, as the dose is directly related to the possibility and extent of health damage.

[0007] Second, regarding public health risks, in-depth research is needed on the probability and severity of various radiation-related diseases that the public may suffer from at different dose levels.

[0008] Third, regarding socio-economic risks, indirect impacts such as economic losses caused by radiation accidents must be considered.

[0009] The risk assessment of off-site radiation caused by the diffusion of radioactive atmospheric plumes is a highly systematic and complex analytical process, which includes calculation of radioactive atmospheric plume diffusion, simulation of nuclide transport processes, simulation of irradiation pathways, calculation of radioactive dose, assessment of health effects, and assessment of economic losses.

[0010] Currently, while some progress has been made in assessing the consequences of off-site radiation incidents in China, it mainly focuses on calculating off-site dose risk, specifically the radioactive dose to the environment from radioactive plumes after a severe accident. However, the impact of radiation accidents is multifaceted and profound, and focusing solely on dose risk has significant limitations.

[0011] Beyond radiation dose calculations, there is an urgent need for a comprehensive assessment of the health risks posed by radionuclides to the public, encompassing a full-cycle analysis of health impacts from acute radiation effects to chronic radiation hazards. A detailed consideration of economic risks is also required, including direct economic losses (such as evacuation and relocation costs, decontamination costs, etc.) and indirect economic losses (such as damage to land value).

[0012] In addition, there is a significant gap in the software systems for off-site radiation risk assessment in China, with a lack of integrated professional software to fully support the entire process of off-site radiation risk assessment.

[0013] In view of this, the inventors of this application have designed a method and system for assessing the full-range off-site radiation risk under severe nuclear power plant accidents, in order to overcome the above-mentioned technical problems. Summary of the Invention

[0014] The technical problem to be solved by this invention is to overcome the shortcomings of existing technology in evaluating the consequences of off-site radiation, which is limited to dose calculation and lacks comprehensive assessment, and to provide a method and system for evaluating the full range of off-site radiation risks under severe nuclear power plant accidents.

[0015] The present invention solves the above-mentioned technical problems through the following technical solution:

[0016] A method for assessing the full-range off-site radiation risk under a severe nuclear power plant accident, characterized in that the method includes:

[0017] S1. Build a basic model architecture for radioactive accident risk assessment, adapt it to model requirements, and establish a corresponding basic database.

[0018] The basic model architecture for radioactive accident risk assessment includes at least: a radioactive accident source term model, a nuclear power plant site model, a meteorological model, an atmospheric diffusion model, a dose risk calculation model, a health risk model, and an economic risk calculation model;

[0019] S2. Constructing the characteristics of radioactive plumes after the accident;

[0020] S3. Calculate the spatial gridding of the accident site and the discretization of plume transport;

[0021] S4. Sample meteorological conditions and simulate plume transport;

[0022] S5. Calculate the radiation dose in the early stage of the grid domain and perform a radiation dose risk assessment;

[0023] S6. Conduct a risk assessment of the health effects in the early stages of the grid domain;

[0024] S7. Calculate the long-term radiation dose in the grid domain and perform a radiation dose risk assessment.

[0025] S8. Conduct a mid- to long-term health effect risk assessment and a mid- to long-term accident consequence assessment.

[0026] According to one embodiment of the present invention, step S2 includes: constructing post-accident radioactive plume characteristics based on the emission characteristics of the accident source term and the release time of the radioactive plume, and clarifying the initial state of the plume.

[0027] According to an embodiment of the present invention, step S3 includes: for the scope of accident analysis, the spatial domain of the accident site is gridded, and the discretization of radioactive plume transport is calculated in units of grid cells.

[0028] According to an embodiment of the present invention, step S4 includes:

[0029] S 41 A meteorological condition sample set is obtained by sampling from a year-round weather sample set;

[0030] S 42 Using the meteorological conditions of the sample set as initial meteorological parameters, the radioactive plume transport process was simulated, and various characteristic parameters of plume transport were calculated.

[0031] S 43 Calculate the remaining radionuclide activity after the radioactive plume passes through the spatial grid.

[0032] According to an embodiment of the present invention, step S 42 The simulation of the intermediate radioactive plume transport process includes:

[0033] S 421 Calculate the basic parameters of plume transport;

[0034] S 422 Calculate the plume rise height;

[0035] S 423 Calculate the plume diffusion parameters;

[0036] S 424 Calculate plume activity.

[0037] According to an embodiment of the present invention, step S5 includes:

[0038] S 51 Using the grid domain as the spatial basis, the ground nuclide deposition concentration and air retention concentration of the plume at a specified location under different meteorological sequence conditions are read as input values ​​to carry out multi-path dose calculation;

[0039] S 52Based on the early stage radiation dose calculation results, conduct an early stage radiation dose risk assessment.

[0040] According to an embodiment of the present invention, step S6 includes:

[0041] S 61 Obtain personnel dosage in the early stages;

[0042] S 62 Perform health effect risk calculations;

[0043] S 63 For each weather sequence in the meteorological sample set, repeat step S. 61 Step S 62 This continues until all weather sequence calculations are completed.

[0044] S 64 Using all the calculation results as input, the transcendental probability algorithm is used to evaluate the results and calculate the mean of the health risk effect and the calculated mean at different probability levels.

[0045] According to an embodiment of the present invention, the assessment objects of the early stage health effects in step S6 include: the spatial distribution of the number of cases with specified health effects, the spatial distribution of cases exceeding the early mortality risk level, the spatial distribution of the number of people with excessive doses in the early stage, the spatial distribution of the average risk of individual direct irradiation, the long-term collective dose distribution of organs in the spatial range, the centerline dose distribution of specified irradiation routes of specified organs in the spatial range, the centerline risk distribution of the axial direction in the spatial range, and the average health effect risk distribution per person in the spatial range.

[0046] According to an embodiment of the present invention, step S7 includes:

[0047] S 71 Using the grid domain as the basic space, the ground nuclide deposition concentrations of each plume segment at a specified location under various meteorological sequence conditions are read.

[0048] S 72 Using the ground-based nuclide deposition concentration as the input value of the model, the long-term ground-based deposition radiation dose, resuspension inhalation radiation dose, and food chain ingestion radiation dose received by personnel were calculated respectively.

[0049] S 73 The medium- and long-term doses caused by the above-mentioned pathways are summed and compared with the protective action level in the relevant standards. The number of meteorological sequences that exceed the protective action level standard is counted and divided by the total number of meteorological sequences to obtain the exceedance probability result.

[0050] According to an embodiment of the present invention, step S8 includes:

[0051] S 81 Obtain personnel dosage in the medium to long term;

[0052] S 82 Perform health effect risk calculations;

[0053] S 83 For each weather sequence in the meteorological sample set, repeat step S. 81 Step S 82 This continues until all weather sequence calculations are completed.

[0054] S 84 Using all the calculation results as input, the transcendental probability algorithm is used to evaluate the results and calculate the mean of the health risk effect and the calculated mean at different probability levels.

[0055] According to an embodiment of the present invention, in step S8, the objects of medium- and long-term health effect evaluation include: the distribution of the number of cases with specified health effects within a spatial range, the spatial distribution of the average risk of individual direct irradiation, the long-term collective dose distribution of organs within a spatial range, the centerline dose distribution of specified irradiation routes of specified organs within a spatial range, the centerline risk distribution of the axial direction within a spatial range, and the average health effect risk distribution per person within a spatial range.

[0056] According to an embodiment of the present invention, in step S8, the objects of the medium- and long-term accident consequence evaluation include: the medium- and long-term population dose, economic cost, maximum effective distance of protective measures, and area / population result affected by the protective measures for the designated organs in the full-range spatial grid.

[0057] The present invention also provides an off-site full-range radiation risk assessment system under severe nuclear power plant accidents, characterized in that the off-site full-range radiation risk assessment system under severe nuclear power plant accidents adopts the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above.

[0058] The off-site full-range radiation risk assessment system under severe nuclear power plant accidents includes:

[0059] The input card reading module is used to obtain basic calculation information;

[0060] The meteorological classification module classifies meteorological samples throughout the year based on atmospheric stability, wind speed, rainfall, and spatial distance, forming a meteorological sample dataset.

[0061] The meteorological sampling module is used to perform sampling algorithms on meteorological samples throughout the year to obtain the meteorological condition sample set used in the calculation;

[0062] Public data pool: Used to store non-process data required for software operation;

[0063] Atmospheric plume diffusion calculation module, used to calculate radioactive plume diffusion parameters;

[0064] The exceedance probability assessment module is used to organize the calculation results of all sampled weather sequences and perform exceedance probability statistical assessment.

[0065] According to one embodiment of the present invention, the evaluation system further includes:

[0066] The geometry calculation module is used to calculate parameters such as fine-scale mesh subdivision and wind direction rotation for early risk calculation.

[0067] The external irradiation correction factor calculation module is used to calculate the external irradiation correction factor by performing bilinear interpolation calculation using the effective size and distance of the plume according to the interpolation table.

[0068] The early recording conversion factor calculation module is used to pre-calculate the dose conversion factor for early dose calculation;

[0069] The early emergency protective measures dose calculation module is used to calculate the early individual dose after taking early emergency protective measures (including relocation, evacuation, and concealment);

[0070] The early radiation risk calculation module is used to calculate the risk of injury and death to individuals due to radioactive nuclides in the early stages;

[0071] The Early Health Effects Assessment Module is used to calculate the early-stage cancer risk of individuals due to radionuclides.

[0072] According to one embodiment of the present invention, the evaluation system further includes:

[0073] The medium- and long-term data preprocessing module is used to load input data and upstream intermediate process data from the public data pool, and at the same time to process the raw data.

[0074] The nuclide table creation module establishes a parent-child sequence table of nuclides based on the nuclide relationships input by the user.

[0075] The medium- and long-term dose factor calculation module is used to calculate the medium- and long-term dose factors of radionuclides.

[0076] The medium-to-long-term ground activity calculation module is used to calculate the total ground sedimentary activity in all areas under medium-to-long-term mist and rain conditions;

[0077] The medium- and long-term dose and protective action calculation module is used to realize the process of radionuclide accumulation in crops and food during the medium- and long-term irradiation phase and the corresponding dose assessment.

[0078] The medium- to long-term health effect calculation module, based on the personnel dose obtained from the medium- to long-term dose and protective action calculation module, and combined with the read health effect parameters, calculates and determines the risk of cancer effects in the medium to long term.

[0079] The present invention also provides an electronic device, characterized in that the electronic device includes: a processor and a memory, the memory storing programs or instructions that can be executed on the processor, the programs or instructions being executed by the processor to implement the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above.

[0080] The present invention also provides a readable storage medium, characterized in that a program or instruction is stored on the readable storage medium, and when the program or instruction is executed by a processor, it realizes the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above.

[0081] The positive and progressive effects of this invention are as follows:

[0082] This invention relates to a method and system for off-site full-range radiation risk assessment under severe nuclear power plant accidents. It achieves integrated modeling of the entire chain, from source term release, atmospheric diffusion, early dose and risk assessment to medium- and long-term health effects and economic consequences. It breaks through the limitations of existing methods that are limited to dose calculation or single-stage risk assessment, and forms a complete off-site full-range radiation risk assessment system. In particular, the calculation process adopts real-time data transmission to achieve dynamic coupling, avoiding truncation errors and information loss caused by module fragmentation in traditional methods, and improving the continuity, accuracy and robustness of the entire calculation process.

[0083] The proposed method and system for assessing the full-range radiation risk outside the nuclear power plant under severe accidents enables a more refined and comprehensive simulation of post-accident dose distribution. Compared to existing methods that mostly only assess the overall dose level or average risk within the accident area, this invention not only outputs the overall results of dose distribution, risk level, and health effects within the accident area at the macroscopic level, but also achieves refined assessment at the microscopic level. By constructing a full-range spatial grid and using multi-pathway dose calculation methods, the risk is further decomposed into individual organ doses, the contributions of different irradiation pathways, and the distribution characteristics of specific health effect types, providing important computational basis for the refined assessment of the consequences of severe accidents.

[0084] The proposed method and system for assessing the full-range radiation risk of a severe nuclear power plant accident also establishes a comprehensive evaluation object and methodology system. This overcomes the limitations of traditional assessments that only analyze consequences from a single perspective. By combining diverse evaluation objects with detailed simulations, it provides detailed evidence for a comprehensive assessment of the radiation consequences after a severe accident, forming a cross-domain, full-cycle assessment framework that can more accurately predict and respond to the multidimensional consequences of severe nuclear power plant accidents. Attached Figure Description

[0085] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0086] Figure 1 The flowchart of the method for assessing the full-range off-site radiation risk under severe nuclear power plant accidents is presented in this invention.

[0087] Figure 2 The calculation flowchart of the off-site full-range radiation risk assessment method under severe nuclear power plant accident of the present invention.

[0088] Figure 3 The calculation flowchart of the early dose calculation module in the method for assessing the full range of off-site radiation risks under severe nuclear power plant accidents of this invention.

[0089] Figure 4 The main process of the medium- and long-term risk assessment model in the off-site full-range radiation risk assessment method under severe nuclear power plant accidents of this invention. Detailed Implementation

[0090] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0091] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0092] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0093] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0094] like Figures 1 to 4 As shown, this invention discloses a method for assessing the full-range off-site radiation risk under severe nuclear power plant accidents, which includes the following steps:

[0095] Step S1: Build the basic model architecture for radioactive accident risk assessment, adapt it to model requirements, and establish the corresponding basic database / set.

[0096] Here, the basic model framework for radioactive accident risk assessment includes:

[0097] I. Radioactive Accident Source Term Model

[0098] The radioactive accident source term model focuses on reasonably characterizing the properties of radioactive materials released from the reactor into the environment under severe accident scenarios. It meticulously classifies source term types, clearly defining the nuclide inventory, chemical form, release fraction, release rate, release time history, release altitude, and release energy parameters to comprehensively describe the release characteristics of radioactive materials.

[0099] II. Nuclear Power Plant Site Model

[0100] The nuclear power plant site model aims to comprehensively present the characteristics of nuclear power plant sites. It integrates site spatial location information, surrounding terrain features, meteorological sample sets, and considers multi-dimensional parameters such as population distribution, land use patterns, and emergency zone delineation, providing comprehensive information support at the site level for risk assessment.

[0101] III. Meteorological Model

[0102] The meteorological model is primarily used to represent the meteorological characteristics of the nuclear power plant area. It covers the initial diffusion parameters corresponding to the stability class AF, and provides hourly datasets of wind speed, wind direction, atmospheric stability, precipitation intensity, and boundary layer height, among other meteorological elements, to provide meteorological conditions for subsequent radioactive material diffusion simulations.

[0103] IV. Atmospheric Diffusion Model

[0104] The atmospheric diffusion model is used to simulate the physical processes of radioactive material transport, diffusion, and wet / dry deposition in the atmosphere. Using meteorological parameters, release source characteristics, and geographical conditions as inputs, it outputs the distribution results of radioactive concentrations and deposition amounts at different times and spatial locations, serving as the core data source for radiation risk assessment and supporting subsequent risk model calculations.

[0105] V. Dosage Risk Calculation Model

[0106] The dose risk calculation model is used to simulate the radiation dose caused by radioactive materials during atmospheric diffusion. It takes population distribution, irradiation pathway, and biological dose conversion coefficient as inputs, and outputs the radiation dose of various organs at different times and spatial locations. The beneficial effect of this invention is that it covers not only conventionally concerned organs such as the whole body, thyroid, and skin, but also various organs such as bone marrow, lungs, stomach, intestines, chest, liver, and bladder, comprehensively quantifying the radiation dose risk of each organ.

[0107] VI. Health Risk Model

[0108] The health risk model is used to quantify the radiation health effects of radioactive materials on people, including deterministic effects (early health effects) and stochastic effects (cancer health effects), transforming dose risk into an intuitive assessment of health impacts and helping to determine the degree of radiation hazard.

[0109] VII. Economic Risk Calculation Model

[0110] The economic risk calculation model described herein is used to quantify the economic impact of radioactive materials on public life, property, and social resources. This invention constructs standardized parameters to assess the economic consequences of actions such as public evacuation, health loss, land decontamination, agricultural product spoilage, and property devaluation.

[0111] The standardized parameters include parameters related to population impact (evacuation costs, refuge costs), parameters related to land and property losses (land decontamination costs, compensation for permanently restricted areas, agricultural product losses, real estate depreciation losses), discount rates, and time factors.

[0112] Step S2: Construct the characteristics of the radioactive plume after the accident.

[0113] Preferably, step S2 includes: constructing post-accident radioactive plume characteristics based on the emission characteristics of the accident source term and the release time of the radioactive plume, and clarifying the initial state of the plume.

[0114] The initial state of the plume includes its horizontal and vertical dimensions, as well as its effective length. The horizontal and vertical dimensions of the plume segment are represented by the standard deviations of the normal distributions of concentration in the horizontal and vertical directions, respectively. and This indicates that the length of a plume segment is determined by the number of plume segments, the duration of each segment, and the wind speed encountered when each segment of the plume is released.

[0115] Step S3: Calculate the spatial gridding of the accident site and the discretization of plume transport.

[0116] Preferably, step S3 includes: for the scope of accident analysis, the spatial domain of the accident site is gridded, and the discretization of radioactive plume transport is calculated in units of grid cells.

[0117] For example, depending on the specific scenario, the fineness of the grid interval can be used to achieve a refined simulation of the radioactive plume, balancing computational efficiency and simulation accuracy, and accurately tracking the transmission trajectory of the plume in space.

[0118] Step S4: Sample meteorological conditions and simulate plume transport.

[0119] Preferably, step S4 includes:

[0120] Step S 41 A meteorological condition sample set is obtained by sampling from a year-round weather sample set.

[0121] Step S 42 Using the meteorological conditions of the sample set as initial meteorological parameters, a simulation of the radioactive plume transport process was conducted to calculate various characteristic parameters of the plume transport. These characteristic parameters include lateral diffusion parameters, vertical diffusion parameters, and dry / wet deposition fractions.

[0122] Preferably, step S 42 The simulation of the intermediate radioactive plume transport process includes:

[0123] Step S 421 Calculate the basic parameters of plume transport.

[0124] Based on information such as plume release time, release source term, and meteorological conditions, the plume release length and the entry and exit time within each spatial grid interval are calculated. The dry and wet deposition fractions of the plume within the spatial grid domain are calculated simultaneously to clarify the basic dynamic parameters during plume transport.

[0125] Step S 422 Calculate the plume rise height.

[0126] Based on the plume's release height, initial meteorological wind speed, heat release rate, etc., the plume's rise height is calculated, and the actual starting position of the plume's transmission in the air is corrected to improve the simulation's realism.

[0127] Step S 423 Calculate the plume diffusion parameters.

[0128] The calculation of plume diffusion parameters is performed by using the Gaussian plume equation to solve for the diffusion parameters. The parameters of each meteorological sample are used as the initial meteorological conditions. The transmission time of each plume segment in each grid is calculated to adapt to the continuous process of plume transmission and realize hourly discretization calculation.

[0129] Step S 424 Calculate plume activity.

[0130] The calculation of plume activity consists of three parts: dry deposition calculation, wet deposition calculation, and nuclide decay calculation.

[0131] Step S 43 The remaining radionuclide activity after the radioactive plume passes through the spatial grid is calculated, including the ground subsidence activity and the air activity at the plume centerline in each spatial grid interval outside the nuclear power plant, clearly showing the spatial distribution of radiation.

[0132] Diffusion parameter correction and model optimization: Two adaptive diffusion correction mechanisms were introduced to address different terrain features in the near and far fields of the plume: ground roughness correction and wind sway effect correction. Ground roughness correction extends the model to fit a wider range of surface conditions. Wind sway effect correction focuses on the area near the release source, optimizing the impact of building wakes on the initial plume size to better reflect real-world scenarios.

[0133] Step S5: Calculate the radiation dose in the early stage of the grid domain and conduct a radiation dose risk assessment.

[0134] Preferably, step S5 includes:

[0135] Step S 51 Using the grid domain as the spatial basis, the ground nuclide deposition concentration and air retention concentration of the plume at the specified location under different meteorological sequence conditions calculated in step S4 above are read as input values ​​to carry out multi-path dose calculation.

[0136] For example, analyzing the irradiation methods: Based on the characteristics of the early stage of the accident, analyze the main irradiation methods in this stage, including air immersion external irradiation, ground external irradiation (8 hours, 7 days), skin irradiation, resuspension irradiation, and inhalation irradiation.

[0137] Protective measures: Match the exposure methods of personnel and determine appropriate protective factors, such as inhalation protective factors and building shielding factors.

[0138] Dose conversion factor preparation: Determine the dose conversion factors of different nuclides for various organs and the whole body, and clarify the dose response relationship between nuclides and organs.

[0139] Nuclide-by-nucleus dose calculation: Using the above conversion factor, the radiation dose to different organs and the whole body of an individual is calculated on a per-nucleus basis, such as the stomach, small intestine, lungs, red bone marrow, thyroid gland, lower intestine, bone surface, breast, testes, ovaries, whole body, adrenal glands, etc., to accurately depict the distribution of radiation hazards.

[0140] Cumulative dose summation: By summarizing the data, we can obtain the cumulative dose to various organs of personnel and the individual effective dose caused by various irradiation methods in the area surrounding the factory after the accident under different meteorological conditions, at designated locations and time periods, to support the assessment of health effects.

[0141] Step S 52 Based on the early stage radiation dose calculation results, conduct an early stage radiation dose risk assessment.

[0142] The total dose is compared with the standard protective action level, the number of meteorological sequences that exceed the standard is counted, and the result is divided by the total number of meteorological sequences to obtain the exceedance probability, which serves as a risk quantification indicator.

[0143] This invention establishes a complete calculation process for each meteorological condition, including atmospheric diffusion calculation, early dose and risk calculation, and medium- and long-term dose and risk calculation. Dynamic coupling is achieved between the calculation modules, and real-time data transfer between modules reduces model fragmentation and truncation errors, enabling integrated calculation throughout the entire calculation cycle. This overcomes the limitations of existing methods that cannot perform cross-dimensional and cross-time-period comprehensive risk assessments within a unified platform.

[0144] Step S6: Conduct a risk assessment of the health effects in the early stages of the grid domain.

[0145] Based on the dose distribution and dose risk distribution within the full-range spatial grid obtained in step S5 above, and combined with the determined early-stage health effect risk calculation formula, an early-stage health effect evaluation is performed. In the early-stage health effect model of this invention, two types of health effects are considered: early death and injury caused by whole-body external irradiation, local external irradiation, and irradiation of specific organs.

[0146] In the assessment of accident consequences, based on all calculation results of the meteorological sample set and the probability of occurrence of meteorological conditions, the probability of each health effect exceeding a given value is assessed using the transcendental probability distribution function.

[0147] Preferably, step S6 includes:

[0148] Step S 61 Obtain personnel doses in the early stages.

[0149] Step S 62 Perform health effect risk calculations.

[0150] The risk of early-stage health effects is calculated using the following formula:

[0151]

[0152] In the formula, rsk represents the health effect risk, and haz represents the hazard coefficient corresponding to the health effect.

[0153] haz is specifically calculated using the following formula:

[0154]

[0155] Among them, D tot D represents the dose induced by the accident on personnel. th The dose threshold that can induce health effects (death, injury); D 50,1 β represents the median mortality / damage dose; β is the risk formula index term.

[0156] The formula introduces a dose threshold, D th When the dose is less than D th In the formula, haz is 0.

[0157] Step S 63 For each weather sequence in the meteorological sample set, repeat step S. 61 Step S 62 This continues until all weather sequence calculations are completed.

[0158] Step S 64 Using all the calculation results as input, the transcendental probability algorithm is used to evaluate the results and calculate the mean of the health risk effect and the calculated mean at different probability levels.

[0159] In particular, the calculations in step S5 above yielded a highly detailed dose and dose-risk profile across the entire spatial range, covering different organs, different types of irradiation, and different effects (early effects and long-term effects). Based on the favorable conditions provided by the above calculations, the present invention possesses the basic conditions for comprehensively assessing the health effects in the early stages.

[0160] Preferably, the present invention identifies eight types of objects for early health effect evaluation, enabling a comprehensive and systematic evaluation of radiation consequences in the early stages of severe accidents, specifically including:

[0161] 1) The distribution of the number of cases of specified health effects within a spatial range.

[0162] 2) Spatial distribution of the risk level above the early mortality level. Based on this result, the size of the region with the risk of early mortality in an accident can be predicted.

[0163] 3) Spatial distribution of the number of people exceeding the dose threshold in the early stage: used to assess the number of people exceeding the dose threshold within a specified grid interval.

[0164] 4) Spatial distribution of average risk of direct exposure to individuals. This risk excludes the dose ingested by the local population from food and water or the dose ingested by decontamination workers in the area, and only considers the direct exposure risk to the population, including plume exposure dose, ground deposition exposure dose, and inhaled exposure dose.

[0165] 5) Long-term collective dose distribution of organs within a spatial range.

[0166] 6) Centerline dose distribution of a specified organ and irradiation pathway within a spatial range.

[0167] 7) Risk distribution along the centerline of the axial direction within the spatial range.

[0168] 8) Per capita health effect risk distribution within a spatial range. Per capita health risk is obtained by calculating the number of health risk cases within a specified area and then dividing by the total population of that area. This reflects the influence of population distribution and wind direction. This risk does not include the doses ingested by the local population from food and water or from decontamination workers. In the early stages, only direct exposure risks are considered, including plume exposure dose, ground deposition exposure dose, inhaled exposure dose, and resuspension inhaled exposure dose.

[0169] Preferably, the types of health effects considered in this invention include early-stage injury risk, early-stage death risk, early-stage cancer death risk, and early-stage cancer damage risk. Organs considered in this invention include the stomach, small intestine, lungs, red bone marrow, thyroid gland, lower intestine, bone surface, breast, testes, ovaries, the whole body, and adrenal glands. Cancer types considered in this invention include bladder cancer, bone cancer, breast cancer, colon cancer, leukemia, liver cancer, lung cancer, stomach cancer, and thyroid cancer.

[0170] This invention establishes a comprehensive evaluation system for radiation risks following severe accidents in the early stages. It constructs a full-range grid along the circumference and axis within the user's analytical space, forming a dose map across the entire spatial area. Targeting early health risk characteristics, it proposes a systematic consequence evaluation effect analysis object. Macroscopically, it can assess spatial dose distribution, personnel dose, and risk distribution; microscopically, it can further assess the dose and radiation risk of specific organs and specific irradiation methods, thus covering the comprehensive evaluation needs of radiation risks in the early stages of severe accidents.

[0171] Step S7: Calculate the long-term radiation dose in the grid domain and conduct a radiation dose risk assessment.

[0172] Preferably, step S7 includes:

[0173] Step S 71 Using the grid domain as the basic space, the ground nuclide deposition concentrations of each plume segment at a specified location under various meteorological sequence conditions are read.

[0174] Step S 72 Using the ground-based nuclide deposition concentration as the input value of the model, the long-term ground-based deposition radiation dose, resuspension inhalation radiation dose, and food chain ingestion radiation dose received by personnel were calculated respectively.

[0175] Step S 73 The medium- and long-term doses caused by the above-mentioned pathways are summed and compared with the protective action level in the relevant standards. The number of meteorological sequences that exceed the protective action level standard is counted and divided by the total number of meteorological sequences to obtain the exceedance probability result.

[0176] Preferably, such as Figure 4 As shown, the specific calculation process for the dosage in the medium to long term is as follows:

[0177] Step 1: Calculate the dose conversion factor of different nuclides on different organs and the whole body of an individual, based on the long-term duration of the accident;

[0178] Step 2: Use these parameters to calculate the radiation dose to different organs and the whole body of an individual using different radionuclides;

[0179] Step 3: Accumulate these data to obtain the cumulative dose and individual effective dose of personnel caused by ground deposition radiation in the area surrounding the factory site under different meteorological conditions and within a specified time period.

[0180] Here, the types of radiation in the medium to long term mainly include: ground-borne radiation, resuspension radiation, and radiation ingested through the food chain. Medium- to long-term health effects include the risk of cancer damage or cancer death.

[0181] The main process for calculating the radiation dose ingested through the food chain in this application includes:

[0182] Step 1: Calculate the leaf absorption factor of various plant products, including forage grass, and calculate the nuclide concentration in forage grass and other plant products based on this. Then calculate the nuclide concentration in animal products (meat and dairy products) and drinking water based on the nuclide concentration.

[0183] Step 2: Integrate the above data on the concentration of radionuclides in food and drinking water to obtain the concentration distribution of various radionuclides in different foods and waters at designated locations around the factory site under different meteorological conditions after the accident.

[0184] Step 3: Based on the calculated concentrations of radionuclides in the food and drinking water, further calculate the radiation dose ingested through the food chain.

[0185] Preferably, the calculation of radiation dose ingested from food in the food chain is as follows:

[0186]

[0187] (Individual dosage)

[0188] Calculation of radiation dose ingested through drinking water:

[0189]

[0190] (Individual dosage)

[0191] in, The concentration of nuclide i in crop j (or water) is expressed in Bq / kg (or Bq / L). Sv / Bq represents the radiation dose conversion factor from radionuclide i to organ k and individual. m represents the planting area of ​​crop j.2 ; Let be the agricultural productivity of crop j, kg / m³ 2 ; For an individual’s intake of crop j (or water), in kg (or L); The total amount of drinking water in the region, m 3 (L); Sv represents the organ and individual dose caused by the irradiation of nuclide i through crop j.

[0192] This step, in dose calculation, does not involve simple formula calculations but considers the impact of different protective measures on the dose, specifically including decontamination, containment, and isolation. Simultaneously, in addition to considering the dose reduction brought about by different protective measures, this step incorporates an economic model to evaluate and calculate the economic costs of each measure. Based on the economic costs and dose results, specific protective measures are determined for different areas. Based on these determined specific protective measures, a more realistic dose distribution within the medium- to long-term spatial grid is iteratively calculated, thereby ensuring the accuracy and authenticity of subsequent dose-risk and post-accident assessments.

[0193] Step S8: Conduct a mid- to long-term health effect risk assessment and a mid- to long-term accident consequence assessment.

[0194] Based on the dose profile and dose risk profile calculated in the refined full-range spatial grid in step S7 above, and combined with the determined formula for calculating the health effect risk in the medium and long term, the health effect assessment in the medium and long term is carried out.

[0195] In the medium- to long-term health effect model of this invention, two types of health effects are considered: cancer death and injury caused by radiation from radioactive deposits due to ground subsidence, radiation from resuspension inhalation, and radiation ingested through the food chain. In the accident consequence assessment, based on all calculation results from the meteorological sample set and the probability of meteorological conditions occurring, a transcendental probability distribution function is used to assess the probability that each health effect outcome exceeds a given value.

[0196] Meanwhile, through the calculation in step S7 above, the dosage, risk, and economic results under different protective measures within the full-range spatial grid are obtained, thus laying a data foundation for a comprehensive mid- to long-term accident consequence assessment.

[0197] More preferably, the method for calculating the health effects risk in the medium to long term is consistent with the method for calculating the health effects in step S6 above.

[0198] More preferably, the present invention identifies six types of objects for evaluating medium- and long-term health effects, enabling a comprehensive evaluation of the radiation consequences in the medium- and long-term stages of severe accidents, specifically including:

[0199] 1) The distribution of the number of health effect cases within a specified spatial range.

[0200] 2) Spatial distribution of average risk of direct exposure for individuals. This risk only considers the direct exposure risk to the population, including ground-deposited radiation dose and resuspension radiation dose;

[0201] 3) Long-term collective dose distribution of organs within a spatial range. Specifically, collective dose considers ground deposition radiation dose, resuspension radiation dose, food chain ingestion radiation dose, and decontamination worker dose;

[0202] 4) Centerline dose distribution of a designated organ along a designated irradiation pathway within a spatial range. Specifically, in the medium to long term, dose types involve ground irradiation dose, total irradiation dose, and resuspension irradiation dose;

[0203] 5) Risk distribution along the centerline of the axial direction within the spatial range. Specifically, the risk types include cancer death risk and cancer damage risk. Specifically, this includes the total risk for each type of cancer and the risk distribution for specific cancers;

[0204] 6) Per capita health effect risk distribution within a spatial range. Per capita health risk is obtained by calculating the number of health risk cases within a specified area and then dividing by the total population of that area. This reflects the influence of population distribution and wind direction. This risk does not include the dose ingested by the local population from food and water or from decontamination workers. Specifically, health effects include the risk of cancer loss and the risk of cancer death. Specifically, the type of exposure includes ground-deposited exposure dose and resuspension inhaled exposure dose.

[0205] Furthermore, considering the complexity of the long-term consequences of Level 3 PSA accidents, this invention establishes a set of accident consequence evaluation objects, excluding health effects, to comprehensively assess the behavioral impacts throughout the long-term post-severe accident phase. Specifically, this includes:

[0206] 1) Mid- to long-term population dose assessment of designated organs using a full-range spatial grid.

[0207] Specifically, the medium- to long-term population dose takes into account the spatial distribution of doses from all sources, including total population dose in the medium- to long-term phase, dose from direct irradiation pathways, total intake dose from the food chain, long-term ground irradiation dose, long-term resuspension irradiation dose, dose received during decontamination of non-farmland, dose received during decontamination of farmland, dose received from ingestion of contaminated dairy products during the growing season, dose received from ingestion of contaminated non-dairy products during the growing season, dose received from ingestion of contaminated dairy products absorbed through long-term root and stem processes, dose received from ingestion of contaminated non-dairy products absorbed through long-term root and stem processes, and dose received from ingestion of wastewater.

[0208] 2) Economic cost assessment.

[0209] Specifically, an economic evaluation of the economic effectiveness of medium- and long-term protection measures within the entire spatial grid is conducted based on an economic model. This evaluation includes the total cost of protection measures, the total cost of non-farmland, the total cost of farmland, the cost of decontamination of non-farmland, the cost of decontamination of farmland, the cost of sealing off non-farmland, the cost of sealing off farmland, the cost of abandoning non-farmland, the cost of abandoning farmland property, the cost of evacuation and resettlement, the cost of discarding dairy products, and the cost of discarding non-dairy products.

[0210] 3) Assessment of the maximum effective distance of the protective measures.

[0211] Specifically, the maximum effective distance of protective measures refers to the maximum range of effect of different protective measures, which can provide an analytical basis for developing emergency plans after a serious accident. Specifically, the protective measures considered in this invention include farmland decontamination, non-farmland decontamination, non-farmland closure, farmland closure, abandonment of property on non-farmland, abandonment of property on farmland, disposal of dairy products, and disposal of non-dairy products.

[0212] 4) Assessment of the area / population results affected by the protection measures.

[0213] Specifically, the specific assessment objects of the area / population affected by the protection measures considered in this invention include the area of ​​the farmland decontamination affected area, the population of the non-farmland decontamination affected area, the area of ​​the farmland enclosure affected area, the population of the non-farmland enclosure affected area, the area of ​​the farmland abandoned property affected area, the population of the non-farmland abandoned property affected area, the area of ​​the dairy product discarded area, and the area of ​​the non-dairy product discarded area.

[0214] This invention, based on atmospheric diffusion calculations and early-stage dose calculations, further couples mid- to long-term dose and risk calculation models, forming a complete system throughout the entire three-stage PSA analysis cycle. This enables full-chain quantitative analysis from the initial stage of an accident to its long-term consequences, overcoming the limitations of existing methods that can only assess a single stage. The data and models at each stage are tightly coupled. Through integrated model and workflow construction, data truncation and error accumulation caused by module fragmentation in traditional methods are eliminated, improving the overall continuity and accuracy of the calculations.

[0215] Due to the tight coupling between models, the transfer loss between models is reduced, enabling the entire method to perform severe accident analysis under more complex factors. This allows for a better characterization and reflection of the spatial impact of radionuclides after a severe accident. Furthermore, for the medium- to long-term consequences of severe accidents, the evaluation method proposed in this invention can not only be used to analyze medium- to long-term dose distribution after a severe accident, but also to provide a basis for decision-making on protective measures after a severe accident.

[0216] Furthermore, based on the above embodiments, the present invention also has some alternative solutions:

[0217] I. Remove some functions or calculation modules. For example, remove the early health effect calculation module or the medium- and long-term health effect calculation module, or merge them into a simplified health risk assessment module.

[0218] 2. Modify or replace some of the radionuclide transfer irradiation pathway networks, such as considering only the accumulation of radionuclides in water bodies or only the accumulation of radionuclides through the food chain.

[0219] Third, improvements to the adaptive model: Customized model adjustments are made to suit the geographical characteristics and climatic conditions of different regions (such as cities, rural areas, and mountainous areas) to enhance the model's regional adaptability. For example, a more accurate diffusion and dose calculation model based on specific geographical features (such as proximity conditions) can be developed.

[0220] Fourth, add long-term environmental impact analysis models, such as assessments of the costs and impacts related to radioactive waste disposal, environmental restoration, and land reconstruction, tailored to specific urban or regional characteristics, so that the consequences analysis after an accident is more realistic.

[0221] Fifth, expand the scope of health effect assessment. Based on the existing health effects, more assessment objects can be further expanded, such as considering long-term radiation effects, the response of the ecological environment to radiation, or risk assessment of different populations (such as special occupational groups, susceptible populations, etc.).

[0222] The present invention also provides an off-site full-range radiation risk assessment system under severe nuclear power plant accidents, which adopts the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above;

[0223] The off-site full-range radiation risk assessment system under severe nuclear power plant accidents includes:

[0224] The input card reading module is used to obtain basic information for calculation, including meteorological data, dose conversion factor, nuclear power plant characteristic parameters, plume release characteristic parameters, early calculation module parameters, and medium- and long-term calculation module parameters.

[0225] The meteorological classification module classifies meteorological samples throughout the year based on atmospheric stability, wind speed, rainfall, and spatial distance, forming a meteorological sample dataset.

[0226] The meteorological sampling module is used to execute sampling algorithms on meteorological samples throughout the year to obtain the meteorological condition sample set used in the calculations. Sampling methods include random sampling and stratified sampling. Random sampling samples 24-hour meteorological data from each day of the year. Stratified sampling quantitatively and randomly selects meteorological samples from the sample stratum obtained from meteorological classification. Each meteorological condition sequence parameter includes wind speed, wind direction, atmospheric stability, and rainfall information.

[0227] Public data pool: Used to store non-process data required for software operation, including user data, calculation results, core output parameters, and other information.

[0228] The atmospheric plume diffusion calculation module is used to calculate the diffusion parameters of radioactive plumes.

[0229] The exceedance probability assessment module is used to organize the calculation results of all sampled weather sequences and perform exceedance probability statistical assessment.

[0230] Preferably, the evaluation system further includes:

[0231] The geometry calculation module is used to calculate parameters such as fine-grained mesh and wind direction rotation for early risk calculation.

[0232] The external irradiation correction factor calculation module is used to calculate the external irradiation correction factor by performing bilinear interpolation calculation using the effective size and distance of the plume according to the interpolation table.

[0233] The early recording conversion factor calculation module is used to pre-calculate the dose conversion factors for early dose calculation, including external irradiation, 8-hour ground irradiation dose factor after the plume passes over the ground, direct inhalation dose factor, resuspension inhalation dose factor, and skin dose factor.

[0234] The Early Emergency Protective Measures Dosage Calculation Module is used to calculate the early individual dose after taking early emergency protective measures (including relocation, evacuation, and concealment).

[0235] The early radiation risk calculation module is used to calculate the risk of injury and death to individuals due to radioactive nuclides in the early stages.

[0236] The Early Health Effects Assessment Module is used to calculate the early-stage cancer risk of individuals due to radionuclides.

[0237] Preferably, the evaluation system further includes:

[0238] The medium- and long-term data preprocessing module is used to load input data and upstream intermediate process data from the public data pool, and at the same time to process the raw data.

[0239] The nuclide table creation module builds a parent-child sequence table of nuclides based on the nuclide relationships input by the user.

[0240] The medium- and long-term dose factor calculation module is used to calculate the medium- and long-term dose factors of radionuclides.

[0241] The medium- to long-term ground activity calculation module is used to calculate the total ground sedimentary activity in all regions under the medium- to long-term plume.

[0242] The medium- and long-term dose and protective action calculation module is used to realize the process of radionuclide accumulation in crops and food during the medium- and long-term irradiation phase and the corresponding dose assessment.

[0243] The medium- to long-term health effect calculation module, based on the personnel dose obtained from the medium- to long-term dose and protective action calculation module, and combined with the read health effect parameters, calculates and determines the risk of cancer effects in the medium to long term.

[0244] In addition, the present invention also provides an electronic device comprising: a processor and a memory, wherein the memory stores a program or instructions executable on the processor, the program or instructions being executed by the processor to implement the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above.

[0245] The present invention also provides a readable storage medium storing a program or instructions, which, when executed by a processor, implements the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described above.

[0246] As described above, the off-site full-range radiation risk assessment method for severe nuclear power plant accidents of the present invention has the following advantages:

[0247] First, it achieves integrated modeling of the entire chain from source term release, atmospheric diffusion, early dose and risk assessment to medium- and long-term health effects and economic consequences, breaking through the limitations of existing methods that are limited to dose calculation or single-stage risk assessment. It forms a complete off-site full-range radiation risk assessment system. In particular, it adopts real-time data transmission to achieve dynamic coupling during the calculation process, avoiding truncation errors and information loss caused by module fragmentation in traditional methods, and improving the continuity, accuracy and robustness of the entire calculation process.

[0248] Second, a more refined and comprehensive post-accident dose distribution simulation: Compared with existing methods that can only assess the overall dose level or average risk within the accident area, this invention can not only output the overall results of dose distribution, risk level and health effects within the accident area at the macro level, but also achieve refined assessment at the micro level. By constructing a full-range spatial grid and a multi-pathway dose calculation method, the risk is further decomposed into the distribution characteristics of individual organ dose, the contribution of different irradiation pathways and specific health effect types, which can provide important calculation basis for the refined assessment of the consequences of serious accidents.

[0249] Third, a comprehensive evaluation object and evaluation method system has been established, which solves the limitations of traditional assessments that only analyze consequences from a single perspective. By combining diversified evaluation objects with detailed simulations, it provides detailed evidence for a comprehensive assessment of the radiation consequences after a serious accident, forming a cross-domain, full-cycle evaluation framework that can more accurately predict and respond to the multidimensional consequences of serious nuclear power plant accidents.

[0250] In summary, the present invention provides a method and system for assessing full-range radiation risks outside the nuclear power plant under severe accidents. Starting from the source term of a severe accident, it simulates the entire transport process of a radioactive plume under severe accident conditions, comprehensively considering the dry and wet deposition of the plume and the loss effects such as radioactive decay, to determine the activity of radionuclides deposited on the ground and remaining in the air within the off-site space. Simultaneously, it simulates the migration process of nuclides in the early and medium-to-long-term timeframes after the passage of the radioactive plume, comprehensively assessing the entire chain and full range of radiation risks, including dose risk, health effect risk, and economic loss risk.

[0251] For those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0252] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0253] Some aspects of this application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The aforementioned hardware or software may be referred to as a "data block," "module," "engine," "unit," "component," or "system." The processor may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. Furthermore, aspects of this application may manifest as computer products residing in one or more computer-readable media, including computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes, etc.), optical discs (e.g., compressed CDs, digital multifunction DVDs, etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.).

[0254] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.

[0255] Similarly, it should be noted that, in order to simplify the description of the embodiments disclosed in this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0256] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for assessing the full-range off-site radiation risk under severe nuclear power plant accidents, characterized in that, The off-site full-range radiation risk assessment method under severe nuclear power plant accidents includes: S1. Build a basic model architecture for radioactive accident risk assessment, adapt it to model requirements, and establish a corresponding basic database. The basic model architecture for radioactive accident risk assessment includes at least: a radioactive accident source term model, a nuclear power plant site model, a meteorological model, an atmospheric diffusion model, a dose risk calculation model, a health risk model, and an economic risk calculation model; S2. Based on the emission characteristics of the accident source term and the release time of the radioactive plume, construct the characteristics of the radioactive plume after the accident; S3. Calculate the spatial gridding of the accident site and the discretization of plume transport using grid cells as units; S4. Sample meteorological conditions and simulate plume transport; Step S4 includes: S 41 A meteorological condition sample set is obtained by sampling from a year-round weather sample set; S 42 Using the meteorological conditions of the sample set as initial meteorological parameters, the radioactive plume transport process was simulated, and various characteristic parameters of plume transport were calculated. The step S 42 The simulation of the intermediate radioactive plume transport process includes: S 421 Calculate the basic parameters of plume transport; S 422 Calculate the plume rise height; S 423 Calculate the plume diffusion parameters; perform the calculation of plume diffusion parameters, use the Gaussian plume equation to solve the diffusion parameters, use the parameters of each meteorological sample as the initial meteorological conditions, calculate the transmission time of each plume segment in each grid, adapt to the continuous process of plume transmission, and realize hourly discretization calculation. Diffusion parameter correction and model optimization: Two adaptive diffusion correction mechanisms were introduced to address the different terrain features in the near and far fields of the plume, namely ground roughness and wind sway effect correction. S 424 Calculate plume activity; S 43 Calculate the remaining radionuclide activity after the radioactive plume passes through the spatial grid; S5. Calculate the radiation dose in the early stage of the grid domain and perform a radiation dose risk assessment; Step S5 includes: S 51 Using the grid domain as the spatial basis, the ground nuclide deposition concentration and air retention concentration of the plume at a specified location under different meteorological sequence conditions are read as input values ​​to carry out multi-path dose calculation; S 52 Based on the early stage radiation dose calculation results, conduct an early stage radiation dose risk assessment; S6. Conduct a risk assessment of the health effects in the early stages of the grid domain; Step S6 includes: S 61 Obtain personnel dosage in the early stages; S 62 Perform health effect risk calculations; The risk of early-stage health effects is calculated using the following formula: ； In the formula, rsk represents the health effect risk, and haz represents the hazard coefficient corresponding to the health effect; haz is specifically calculated using the following formula: ； Among them, D tot D represents the dose induced by the accident on personnel. th The dose threshold that can induce health effects (death, injury); D 50,1 The median mortality / injury dose; β is the risk index term in the risk formula; when the dose is less than D... th In the formula, haz is 0; S 63 For each weather sequence in the meteorological sample set, repeat step S. 61 Step S 62 This continues until all weather sequence calculations are completed. S 64 Using all the calculation results as input, the transcendental probability algorithm is used to evaluate the results and calculate the mean of the health risk effect and the calculated mean under different probability levels. S7. Calculate the long-term radiation dose in the grid domain and perform a radiation dose risk assessment. Step S7 includes: S 71 Using the grid domain as the basic space, the ground nuclide deposition concentrations of each plume segment at a specified location under various meteorological sequence conditions are read. S 72 Using the ground-based nuclide deposition concentration as the input value of the model, the long-term ground-based deposition radiation dose, resuspension inhalation radiation dose, and food chain ingestion radiation dose received by personnel were calculated respectively. S 73 The medium- and long-term doses caused by the above-mentioned pathways are summed and compared with the protective action level in the relevant standards. The number of meteorological sequences that exceed the protective action level standard is counted and divided by the total number of meteorological sequences to obtain the exceedance probability result. S8. Conduct a medium- to long-term health effect risk assessment and a medium- to long-term accident consequence assessment. Step S8 includes: S 81 Obtain personnel dosage in the medium to long term; S 82 Perform health effect risk calculations; S 83 For each weather sequence in the meteorological sample set, repeat step S. 81 Step S 82 This continues until all weather sequence calculations are completed. S 84 Using all the calculation results as input, the transcendental probability algorithm is used to evaluate the results and calculate the mean of the health risk effect and the calculated mean at different probability levels.

2. The off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in claim 1, characterized in that, Step S2 includes: constructing the characteristics of the radioactive plume after the accident based on the emission characteristics of the accident source term and the release time of the radioactive plume, and clarifying the initial state of the plume.

3. The off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in claim 1, characterized in that, Step S3 includes: for the scope of accident analysis, the spatial domain of the accident site is gridded, and the discretization of radioactive plume transport is calculated in units of grid cells.

4. The off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in claim 1, characterized in that, The assessment objects of early-stage health effects in step S6 include: the spatial distribution of the number of cases with specified health effects, the spatial distribution of cases exceeding the early mortality risk level, the spatial distribution of the number of people with excessive doses in the early stage, the spatial distribution of the average risk of individual direct irradiation, the long-term collective dose distribution of organs in the spatial range, the centerline dose distribution of specified organs and irradiation routes in the spatial range, the centerline risk distribution along the axial direction in the spatial range, and the average health effect risk distribution per person in the spatial range.

5. The off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in claim 1, characterized in that, In step S8, the objects of medium- and long-term health effect evaluation include: the distribution of the number of cases with specified health effects within a spatial range, the spatial distribution of the average risk of individual direct irradiation, the long-term collective dose distribution of organs within a spatial range, the centerline dose distribution of specified irradiation routes for specified organs within a spatial range, the centerline risk distribution along the axial direction within a spatial range, and the average health effect risk distribution per person within a spatial range.

6. The off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in claim 1, characterized in that, In step S8, the objects of the medium- and long-term accident consequence evaluation include: the medium- and long-term population dose, economic cost, maximum effective distance of protective measures, and area / population result affected by the protective measures for the designated organs in the full-range spatial grid.

7. A full-range off-site radiation risk assessment system for severe accidents at nuclear power plants, characterized in that, The off-site full-range radiation risk assessment system under severe nuclear power plant accident adopts the off-site full-range radiation risk assessment method under severe nuclear power plant accident as described in any one of claims 1-6; The off-site full-range radiation risk assessment system under severe nuclear power plant accidents includes: The input card reading module is used to obtain basic calculation information; The meteorological classification module classifies meteorological samples throughout the year based on atmospheric stability, wind speed, rainfall, and spatial distance, forming a meteorological sample dataset. The meteorological sampling module is used to perform sampling algorithms on meteorological samples throughout the year to obtain the meteorological condition sample set used in the calculation; Public data pool: Used to store non-process data required for software operation; Atmospheric plume diffusion calculation module, used to calculate radioactive plume diffusion parameters; The exceedance probability assessment module is used to organize the calculation results of all sampled weather sequences and perform exceedance probability statistical assessment.

8. The off-site full-range radiation risk assessment system under severe nuclear power plant accidents as described in claim 7, characterized in that, The evaluation system also includes: The geometry calculation module is used to calculate parameters such as fine-scale mesh subdivision and wind direction rotation for early risk calculation. The external irradiation correction factor calculation module is used to calculate the external irradiation correction factor by performing bilinear interpolation calculation using the effective size and distance of the plume according to the interpolation table. The early recording conversion factor calculation module is used to pre-calculate the dose conversion factor for early dose calculation; The early emergency protective measures dose calculation module is used to calculate the early individual dose after taking early emergency protective measures; The early radiation risk calculation module is used to calculate the risk of injury and death to individuals due to radioactive nuclides in the early stages; The Early Health Effects Assessment Module is used to calculate the early-stage cancer risk of individuals due to radionuclides.

9. The off-site full-range radiation risk assessment system under severe nuclear power plant accidents as described in claim 7, characterized in that, The evaluation system also includes: The medium- and long-term data preprocessing module is used to load input data and upstream intermediate process data from the public data pool, and at the same time to process the raw data. The nuclide table creation module establishes a parent-child sequence table of nuclides based on the nuclide relationships input by the user. The medium- and long-term dose factor calculation module is used to calculate the medium- and long-term dose factors of radionuclides. The medium-to-long-term ground activity calculation module is used to calculate the total ground sedimentary activity in all areas under medium-to-long-term mist and rain conditions; The medium- and long-term dose and protective action calculation module is used to realize the process of radionuclide accumulation in crops and food during the medium- and long-term irradiation phase and the corresponding dose assessment. The medium- to long-term health effect calculation module, based on the personnel dose obtained from the medium- to long-term dose and protective action calculation module, and combined with the read health effect parameters, calculates and determines the risk of cancer effects in the medium to long term.

10. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing programs or instructions that can run on the processor, the programs or instructions being executed by the processor to implement the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described in any one of claims 1-6.

11. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions, which, when executed by a processor, implement the off-site full-range radiation risk assessment method under severe nuclear power plant accidents as described in any one of claims 1-6.

Images