Method and device for calculating concentration of gaseous tritium discharged by nuclear facility and method and device for evaluating concentration of gaseous tritium discharged by nuclear facility

Abstract

The invention discloses a method and a device for calculating the concentration of gaseous tritium discharged by a nuclear facility and an evaluation method and a device. The method comprises the following steps: acquiring meteorological data, environmental parameters and discharge parameters of the nuclear facility; determining an atmospheric dispersion factor of gaseous tritium discharged by the nuclear facility based on the meteorological data, the environmental parameters and the discharge parameters; determining a re-evaporation factor of the discharged gaseous tritium based on the atmospheric dispersion factor, the deposition property of the gaseous tritium, meteorological data and environmental parameters; determining a reevaporation dispersion factor of gaseous tritium based on the meteorological data, the environmental parameters and the reevaporation factor; and adding the atmospheric dispersion factor and the reevaporation dispersion factor to obtain the concentration of the gaseous tritium discharged by the nuclear facility. The method can accurately evaluate the concentration of gaseous tritium in the surrounding environment after the nuclear facility discharges gaseous tritium.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear power technology, and in particular relates to a method and device for calculating the concentration of gaseous tritium discharged from a nuclear facility, and a method and device for evaluating the concentration of gaseous tritium discharged from a nuclear facility. Background Art

[0002] During the operation of nuclear facilities, gaseous tritium is produced, which is mainly released into the atmosphere in the form of tritiated hydrogen (HT) and tritiated water (HTO). In the case of normal operation and accidental discharge of nuclear facilities, the radiation environmental impact of effluents containing radionuclides needs to be evaluated.

[0003] However, the gaseous tritium emitted into the atmosphere by the airborne pathway is also accompanied by a coupled transfer process between the atmosphere and other environmental compartments during the atmospheric diffusion process. Tritium in the air is transferred to the soil through dry and wet deposition pathways, and after physical and chemical reactions in the soil, part of it will evaporate into the air again. The evaporated gaseous tritium will diffuse again in the atmospheric environment. Therefore, the existing technology has a large error in the concentration assessment of gaseous tritium emitted into the atmosphere by nuclear facilities. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and device for calculating the concentration of gaseous tritium emitted by nuclear facilities and a method and device for evaluating the concentration of gaseous tritium emitted by nuclear facilities in view of the above-mentioned deficiencies in the prior art. The method can be used to accurately evaluate the concentration of gaseous tritium emitted by nuclear facilities.

[0005] In a first aspect, an embodiment of the present invention provides a method for calculating the concentration of gaseous tritium emitted by a nuclear facility, comprising:

[0006] Acquiring meteorological data, environmental parameters and emission parameters of the nuclear facility, wherein the environmental parameters are parameters of the external environment of the nuclear facility;

[0007] Determine the atmospheric diffusion factor of the gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters, wherein the atmospheric diffusion factor is the ratio of the concentration of the gaseous tritium emitted by the nuclear facility after diffusion in the atmosphere to the emission rate of the gaseous tritium;

[0008] Determine the re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters, wherein the re-evaporation factor is the amount of the gaseous tritium deposited on the surface that re-enters the atmosphere through the re-evaporation process;

[0009] Determining a re-evaporation diffusion factor of gaseous tritium based on the meteorological data, environmental parameters and the re-evaporation factor, wherein the re-evaporation diffusion factor is a ratio of a concentration of re-evaporated gaseous tritium after diffusion in the atmosphere to a release rate of gaseous tritium;

[0010] Based on the atmospheric diffusion factor and the re-evaporation diffusion factor, the concentration of gaseous tritium emitted by the nuclear facility is obtained.

[0011] In a second aspect, an embodiment of the present invention further provides a device for calculating the concentration of gaseous tritium discharged from a nuclear facility, comprising:

[0012] An acquisition module, used to acquire meteorological data, environmental parameters and emission parameters of the nuclear facility, wherein the environmental parameters are parameters of the external environment of the nuclear facility;

[0013] a first calculation module, connected to the acquisition module, for determining the atmospheric diffusion factor of the gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters, wherein the atmospheric diffusion factor is the ratio of the concentration of the gaseous tritium emitted by the nuclear facility after diffusion in the atmosphere to the release rate of the gaseous tritium;

[0014] A second calculation module, connected to the acquisition module, is used to determine the re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters, wherein the re-evaporation factor is the amount of the gaseous tritium deposited on the surface that re-enters the atmosphere through the re-evaporation process;

[0015] a third calculation module, respectively connected to the acquisition module, the first calculation module and the second calculation module, for determining a re-evaporation diffusion factor of gaseous tritium based on the meteorological data, the environmental parameters and the re-evaporation factor, wherein the re-evaporation diffusion factor is a ratio of a concentration of re-evaporated gaseous tritium after diffusion in the atmosphere to a release rate of the gaseous tritium;

[0016] The fourth calculation module is connected to the first calculation module and the third calculation module, and is used to obtain the concentration of gaseous tritium emitted by the nuclear facility based on the atmospheric diffusion factor and the re-evaporation diffusion factor.

[0017] In a third aspect, an embodiment of the present invention further provides a nuclear facility safety assessment method.

[0018] Characterized in that the method comprises:

[0019] According to the method for calculating the concentration of gaseous tritium emitted by a nuclear facility as described in the first aspect above, the concentration of gaseous tritium corresponding to a plurality of calculation points in the external environment of the nuclear facility is obtained;

[0020] Based on the concentrations of gaseous tritium corresponding to the multiple calculation points, a safety assessment is performed on the nuclear facility.

[0021] In a fourth aspect, an embodiment of the present invention further provides a nuclear facility safety assessment device,

[0022] The invention is characterized by comprising:

[0023] The device for calculating the concentration of gaseous tritium emitted by a nuclear facility as described in the third aspect is used to obtain the concentration of gaseous tritium corresponding to multiple calculation points in the external environment of the nuclear facility;

[0024] A safety assessment module is connected to the concentration calculation device and is used to perform a safety assessment on the nuclear facility based on the concentration of gaseous tritium corresponding to the multiple calculation points. The concentration calculation method of gaseous tritium emitted by nuclear facilities of the present invention comprehensively considers the migration and transformation process of gaseous tritium in the environment by combining the atmospheric diffusion factor and the re-evaporation diffusion factor. By considering the re-evaporation process, the simulation accuracy of the environmental behavior of gaseous tritium is improved, thereby improving the accuracy of the calculation of the concentration of gaseous tritium. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : A flow chart of a method for calculating the concentration of gaseous tritium emitted from a nuclear facility provided in an embodiment of the present invention;

[0026] Figure 2 : A schematic diagram of the process of HTO re-evaporation and diffusion in soil provided by an embodiment of the present invention;

[0027] Figure 3 : A flow chart of a method for calculating tritium concentration in the atmospheric environment surrounding a nuclear facility based on the re-evaporation effect provided in an embodiment of the present invention;

[0028] Figure 4 : A structural diagram of a device for calculating the concentration of gaseous tritium emitted by a nuclear facility provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0030] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0031] At present, when calculating the diffusion law of tritiated hydrogen emitted by nuclear facilities and the concentration of tritiated hydrogen in the surrounding environment in engineering and scientific research, whether based on Gaussian model or more accurate random walk model, numerical method, etc., only the contribution of tritium to the environmental concentration after one atmospheric diffusion after release is calculated. The atmospheric diffusion process of tritiated hydride is also accompanied by the coupled transfer process between the atmosphere and other environmental compartments. Tritium in the air is transferred to the soil through dry deposition and wet deposition, and after physical and chemical reactions in the soil (such as oxidation of HT), it will partially evaporate into the air, which is called the re-evaporation effect. Therefore, the concentration of tritium in the air is the sum of the concentration of tritium after one atmospheric diffusion after release and the concentration of secondary atmospheric diffusion of soil re-evaporation surface sources. For tritiated hydrogen (HT) released by nuclear facilities in the form of tritiated hydrogen, it will be oxidized into tritiated water (HTO) after being deposited in the soil and evaporate again into the atmosphere. Since HTO will be taken into the body, distributed in various tissues and organs and participate in metabolism, its radiation dose to the organism is much higher than that of HT of the same activity. Therefore, when calculating the radiation dose of HT released by nuclear facilities, the contribution of its oxidation and re-evaporation effects is more important.

[0032] Tritium released into the atmosphere by airborne pathways is accompanied by a coupled transfer process between the atmosphere and other environmental compartments during the atmospheric diffusion process. Tritium in the air is transferred to the soil through dry and wet deposition pathways. After physical and chemical reactions in the soil (such as oxidation of HT), part of it will evaporate into the air again, and the evaporated tritiated hydrogen will diffuse again in the atmosphere. Since the amount of tritium released by the current pressurized water reactor airborne pathway is small and its contribution to the radiation dose of the public and organisms is low, when calculating the tritium concentration in the atmosphere around the pressurized water reactor, only the contribution of the atmospheric diffusion process after its release to the air concentration is considered, and the tritium concentration that evaporates again from the soil into the atmosphere is not calculated. For fast reactors and future fusion reactors, which release more tritiated hydrogen, if the current method is still used, the calculated tritiated hydrogen concentration will be somewhat different from the actual scenario. In order to obtain more accurate calculation results, it is necessary to propose a method that considers the contribution of the tritiated hydrogen re-evaporation effect to the atmospheric concentration.

[0033] Embodiment 1:

[0034] Based on the above research, in order to solve the existing technical problems, such as Figure 1 As shown, this embodiment provides a method for calculating the concentration of gaseous tritium emitted by a nuclear facility, including the following steps 101 to 105.

[0035] Step 101, obtaining meteorological data, environmental parameters and emission parameters of nuclear facilities.

[0036] Meteorological data include: wind speed, wind direction, atmospheric stability, rainfall, etc. Environmental parameters include: information on the external environment of nuclear facilities such as topographic features and surface properties. Emission parameters include: emission rate and emission height of gaseous tritium, etc.

[0037] Meteorological data reflects the weather and atmospheric conditions at the location of nuclear facilities, and has an important impact on the diffusion, deposition and re-evaporation of gaseous tritium in the atmosphere. It can be obtained through meteorological station monitoring data, on-site observations, numerical weather forecast models, etc.

[0038] Environmental parameters involve the geographical and ecological characteristics of the nuclear facility location and surrounding environment. They have an important impact on the deposition, re-evaporation, and migration and transformation of gaseous tritium in the environmental medium. They can be collected through geographic information system (GIS) data, remote sensing images, field surveys, etc.

[0039] Emission parameters reflect the emission characteristics of nuclear facilities and are the basis for calculating the intensity of pollution sources. They include the emission rate of gaseous tritium, that is, the total amount of gaseous tritium emitted into the environment by nuclear facilities per unit time, usually in becquerels (Bq / s). They can be obtained through nuclear facility operation data, design parameters, online monitoring, etc.

[0040] Meteorological data and emission data should correspond in time, and environmental parameters should cover the calculation area in space. For real-time calculation or long-term evaluation, meteorological data and emission data need to be continuously updated to reflect actual changes.

[0041] In nuclear reactors, tritium is usually produced by reacting lithium with neutrons. Tritium exists in the form of gas during the nuclear reaction, forming tritiated hydrogen and tritiated water.

[0042] Step 102, determining the atmospheric dispersion factor of gaseous tritium emitted from the nuclear facility based on meteorological data, environmental parameters and emission parameters.

[0043] Among them, the atmospheric diffusion factor is the ratio of the concentration of gaseous tritium emitted by nuclear facilities after diffusion in the atmosphere to the emission rate of gaseous tritium. The atmospheric diffusion factor (usually expressed as (χ / Q)) refers to the average concentration (χ) of pollutants of unit source strength (Q) at a certain receptor point (calculation point) after diffusion through the atmosphere. It indicates the contribution of a unit amount of pollutants released by the pollution source to the concentration at a certain point in the environment. Calculating the atmospheric diffusion factor can predict the concentration distribution of gaseous tritium at different distances and directions, and then evaluate the impact of nuclear facilities on the surrounding environment and public health.

[0044] Based on the meteorological data, environmental parameters and emission parameters obtained above, the concentration of gaseous tritium after diffusion in the atmosphere is calculated. Specifically, an atmospheric diffusion model, such as a Gaussian model, may be used.

[0045] Step 103, determining the re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters.

[0046] Reevaporation refers to the process by which gaseous tritium that has been deposited on the surface (including soil, vegetation and water bodies) returns to the atmosphere through physical and biological processes. The reevaporation factor is the amount of gaseous tritium that has been deposited on the surface that re-enters the atmosphere through the reevaporation process. The reevaporated tritium returns to the atmosphere mainly in the form of tritiated water (HTO).

[0047] After the gaseous tritium emitted by nuclear facilities enters the atmosphere, it will undergo a series of migration and transformation processes in the environment. Among them, some gaseous tritium will be deposited on the surface and then re-enter the atmosphere through the re-evaporation process. This process has an important impact on the distribution and concentration of tritium in the environment.

[0048] In one example, the reevaporation factor may be calculated as follows:

[0049] (1) Calculate the deposition flux (deposition rate) of tritium: Calculate the deposition flux of tritium per unit area of ​​the surface based on the atmospheric diffusion factor and the deposition rate; (2) Establish a dynamic equilibrium model of the surface tritium reservoir: Consider the accumulation, decay and re-evaporation process of tritium on the surface. (3) Calculate the re-evaporation flux: Apply the re-evaporation model, consider meteorological conditions and surface parameters, and calculate the re-evaporation flux of tritium. (4) Determine the re-evaporation factor: The re-evaporation factor is equal to the product of the re-evaporation flux and the surface area.

[0050] Step 104, based on the meteorological data, environmental parameters and the reevaporation factor, determine the reevaporation diffusion factor of the gaseous tritium, where the reevaporation diffusion factor is the ratio of the concentration of the reevaporated gaseous tritium after diffusion in the atmosphere to the gaseous tritium emission rate.

[0051] Step 105, determining the re-evaporation dispersion factor of gaseous tritium based on the meteorological data, environmental parameters and the re-evaporation factor.

[0052] Among them, the reevaporation diffusion factor is the ratio of the concentration of reevaporated gaseous tritium after diffusion in the atmosphere (the concentration of gaseous tritium at the receptor point under the condition of unit reevaporation source strength) to the gaseous tritium emission rate. The reevaporation source strength is the total amount of gaseous tritium reevaporated into the atmosphere per unit time (which can be calculated based on the reevaporation factor and the reevaporation area).

[0053] Around nuclear facilities, the re-evaporated gaseous tritium on the surface will re-enter the atmosphere, forming a new source of pollution. In order to evaluate the impact of re-evaporated gaseous tritium on the environment and public health, it is necessary to calculate its diffusion concentration in the atmosphere based on the re-evaporation diffusion factor.

[0054] Specifically, after determining the re-evaporation factor of gaseous tritium, the re-evaporation dispersion factor can be calculated using an atmospheric diffusion model. For surface sources, the re-evaporated gaseous tritium is released from the surface in a continuous manner, close to the ground, and the effective emission height is approximately zero.

[0055] For example, the Gaussian Plume Model is often used to calculate the diffusion of pollutants from continuous point sources. For reevaporation surface sources, the surface source can be converted into a superposition of multiple line sources or point sources through equivalent processing. Surface source model: Directly calculating the diffusion of surface sources can more accurately reflect the characteristics of surface reevaporation.

[0056] Step 106, obtaining the concentration of gaseous tritium emitted from the nuclear facility according to the atmospheric diffusion factor and the re-evaporation diffusion factor.

[0057] Specifically, the emitted gaseous tritium will directly affect the environment through atmospheric diffusion. At the same time, after being deposited on the surface, it will re-enter the atmosphere through re-evaporation, increasing the tritium concentration in the air. In order to comprehensively evaluate the concentration of tritium in the air, it is necessary to consider the contribution of directly emitted gaseous tritium: through atmospheric diffusion calculation, the ratio of the concentration of directly emitted gaseous tritium at the receptor point to the gaseous tritium emission rate (atmospheric diffusion factor) is obtained; and the contribution of re-evaporated gaseous tritium: through re-evaporation diffusion calculation, the ratio of the concentration of surface re-evaporated gaseous tritium at the receptor point to the gaseous tritium emission rate (re-evaporation diffusion factor) is obtained. Combining the concentration contributions of the above two parts, the total gaseous tritium concentration at the receptor point can be obtained.

[0058] Optionally, the above step 102 may specifically include:

[0059] In the case of long-term emission of gaseous tritium from nuclear facilities, the atmospheric dispersion factor is calculated using the following formula (1):

[0060]

[0061] When the emission of gaseous tritium from nuclear facilities is short-term, the atmospheric dispersion factor is calculated using the following formula (2):

[0062]

[0063] Where (χ / Q) is the first atmospheric diffusion factor of gaseous tritium, x is the downwind distance from the calculation point to the release point, the calculation point is a location used to monitor or evaluate the concentration of tritium at a specific location, Q is the release rate of gaseous tritium; u is the wind speed at the release height, y is the crosswind distance, z is the height of the calculation point, H is the effective height of the release point, σ y , σ z are the horizontal and vertical diffusion parameters respectively. y , σz It is related to the atmospheric stability of the environment and the distance to the release point. This parameter is obtained through atmospheric diffusion experiments in engineering practice.

[0064] The above step 106 specifically includes: adding the atmospheric diffusion factor and the re-evaporation diffusion factor to obtain the concentration of gaseous tritium emitted by the nuclear facility.

[0065] The atmospheric dispersion factor is used to describe the relationship between the concentration of gaseous tritium emitted by nuclear facilities after diffusion in the atmosphere and the emission rate of gaseous tritium. The χ in (χ / Q) can represent the concentration of gaseous tritium at the receptor point (calculation point) under unit source strength (release rate Q).

[0066] Specifically, in the environmental impact assessment and safety analysis of nuclear facilities, calculating the concentration of gaseous tritium in the atmosphere is crucial to assessing the impact on the environment and the public. As a radioactive isotope, tritium is usually emitted in gaseous form, and its diffusion behavior in the atmosphere needs to be predicted by an atmospheric dispersion model.

[0067] When a nuclear facility continuously and stably emits gaseous tritium (i.e., long-term emissions, such as average emissions throughout the year or over many years, or other normal operating conditions), the calculation model of formula (1) above is used to calculate the atmospheric diffusion factor of gaseous tritium. When a nuclear facility emits gaseous tritium over a relatively short period of time, such as short-term emissions caused by hours, days, or specific events (safety accidents), the calculation model of formula (2) above can be used to calculate the atmospheric diffusion factor.

[0068] In this embodiment, the concentration distribution of gaseous tritium in the atmosphere can be accurately estimated under different emission conditions (long-term or short-term), providing a scientific basis for environmental impact assessment, predicting the potential impact range of gaseous tritium in the environment surrounding nuclear facilities, and providing a reference for emission control measures, emergency plan formulation and environmental management of nuclear facilities.

[0069] Optionally, the gaseous tritium includes tritiated hydrogen and tritiated water, and the above step 103 may specifically include the following steps:

[0070] Based on the atmospheric diffusion factor, the deposition properties of gaseous tritium and meteorological data, the deposition amount of gaseous tritium is determined according to the deposition effect. The deposition factors of gaseous tritium include the deposition factors of tritiated hydrogen and tritiated water.

[0071] The reevaporation factor of tritiated hydrogen is obtained according to the deposition factor of tritiated hydrogen, the oxidation ratio and the reevaporation ratio of tritiated water. The oxidation ratio is the ratio of tritiated hydrogen oxidized to tritiated water in the soil.

[0072] According to the deposition factor of tritiated water and the re-evaporation ratio of tritiated water, the re-evaporation factor of tritiated water is obtained.

[0073] The re-evaporation factor of gaseous tritium includes the re-evaporation factor of tritiated hydrogen and the re-evaporation factor of tritiated water.

[0074] The reevaporation factor refers to the amount of gaseous tritium deposited on the surface that re-enters the atmosphere through physical and chemical processes.

[0075] Specifically, first, the dry deposition of tritiated hydrogen is calculated; then, the dry deposition and wet deposition of tritiated water are calculated; tritiated hydrogen has a certain oxidation ratio in the soil and is partially converted into tritiated water. According to the oxidation amount of tritiated hydrogen and the re-evaporation ratio of tritiated water, the re-evaporation factor of tritiated hydrogen is calculated; at the same time, the deposition amount and re-evaporation ratio of tritiated water in the atmosphere are used to obtain the re-evaporation factor of tritiated water. The sum of the re-evaporation factor of tritiated hydrogen and the re-evaporation factor of tritiated water is the total re-evaporation factor.

[0076] In this embodiment, the physical and chemical transformation processes of gaseous tritium in the environment are fully considered, which improves the accuracy of the assessment of tritium's environmental behavior, helps in environmental risk assessment, and provides a scientific basis for emission control, environmental monitoring, and management decisions of nuclear facilities.

[0077] Optionally, the deposition properties of the gaseous tritium include a dry deposition factor of tritiated hydrogen and dry and wet deposition factors of tritiated water, and the meteorological data include a rainfall wash coefficient, rainfall, and wind speed.

[0078] Based on the atmospheric diffusion factor, the deposition properties of gaseous tritium, and meteorological data, the deposition amount of gaseous tritium is determined according to the deposition effect, including:

[0079] According to the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor, the dry deposition factor is obtained. The dry deposition factor is used to characterize the amount of tritiated hydrogen directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion.

[0080] According to the dry deposition rate of tritiated water and the atmospheric diffusion factor, the dry deposition factor of tritiated water is obtained. The dry deposition factor of tritiated water is used to characterize the amount of tritiated water directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion.

[0081] According to the rainfall, rainfall washing coefficient and wind speed, the wet deposition factor of tritiated water is obtained. The wet deposition factor of tritiated water is used to characterize the amount of tritiated water washed out of the atmosphere by precipitation processes such as rain or snow and deposited on the surface.

[0082] The dry deposition rate is the speed at which pollutants are directly deposited from the atmosphere to the surface in the absence of precipitation, and is measured in m / s. It can be determined based on the physical and chemical properties of the pollutants, surface characteristics, and meteorological conditions.

[0083] The rainfall flushing coefficient indicates the efficiency of rainfall in removing pollutants from the atmosphere, and its unit is s. -1It can be determined by parameters such as the solubility of pollutants, rainfall intensity and particle size, for example, it can be obtained by combining engineering experience and environmental conditions around nuclear facilities.

[0084] Rainfall and rainfall intensity, usually expressed in mm / h, affect the wet deposition rate. The greater the rainfall, the higher the wet deposition rate.

[0085] Specifically, based on the deposition effect, the deposition of gaseous tritium can be divided into the following parts: dry deposition of tritiated hydrogen, dry deposition of tritiated water, and wet deposition of tritiated water. By accurately calculating the dry and wet deposition of gaseous tritium, the migration and accumulation process of tritium in the environment can be fully evaluated.

[0086] Optionally, the dry deposition factor is obtained according to the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor, specifically including:

[0087] The dry deposition factor is calculated by formula (3):

[0088] DP HT =(χ / Q)×V d,HT (3)

[0089] Among them, DP HT is the dry deposition factor of tritiated hydrogen, (χ / Q) is the atmospheric diffusion factor of gaseous tritium, V d,HT is the dry deposition rate of tritiated hydrogen.

[0090] Specifically, the dry deposition factor, i.e., the amount of tritiated hydrogen directly deposited from the atmosphere to the surface, can be obtained based on the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor. The dry deposition factor of tritiated hydrogen can be accurately calculated using the above formula (3), which provides a scientific basis for evaluating the deposition process and potential impact of tritium in the environment, and helps to strengthen the environmental management of nuclear facility emissions and the formulation of protective measures.

[0091] Optionally, the above method of obtaining the dry deposition factor of tritiated water according to the dry deposition rate of tritiated water and the atmospheric diffusion factor may specifically include the following steps:

[0092] Based on the same principle, the dry deposition factor of tritiated water can be obtained by the following calculation:

[0093] DP HTO =(χ / Q)×V d,HTO

[0094] Among them, DP HTO is the dry deposition factor of tritiated water, (χ / Q) is the atmospheric diffusion factor of gaseous tritium, V d,HTO is the dry deposition rate of tritiated water.

[0095] Optionally, the wet deposition factor of tritiated water is obtained according to the rainfall, rainfall flushing coefficient and wind speed, specifically including:

[0096] The wet deposition factor of tritiated water is calculated by formula (4):

[0097]

[0098] Where DW is the wet deposition factor of tritiated water, u is the wind speed at the release height, x is the downwind distance of the calculation point from the release point, the calculation point is the location used to monitor or evaluate the concentration of tritium at a specific location, a and b are rainfall flushing coefficients, a is in 1 / s, b is dimensionless, and L is the rainfall.

[0099] Specifically, rainfall has a significant effect on the deposition of gaseous tritium, especially through the wet deposition process. The wet deposition amount of tritiated water in gaseous tritium can be calculated by rainfall, rainfall flushing coefficient and wind speed, that is, the amount of tritiated water deposited to the surface by rainfall washing under rainfall conditions. The wet deposition factor of tritiated water can be accurately calculated by combining the above formula (4) with rainfall, rainfall flushing coefficient and wind speed.

[0100] Optionally, the re-evaporation factor of tritiated hydrogen is obtained according to the dry deposition factor of tritiated hydrogen, the oxidation ratio and the re-evaporation ratio of tritiated water, and specifically includes:

[0101] Determine the calculation domain, which is a circular area with the calculation point as the origin and a radius as a preset distance, and the calculation domain includes k sub-areas;

[0102] The re-evaporation factor of tritiated hydrogen is calculated by the following formula (5):

[0103] RE HT,(k,j) =DP HT,(k,j) ×A k ×k oxi × j (5)

[0104] Among them, RE HT,(k,j) is the re-evaporation factor of tritiated hydrogen in sub-area k at the jth time step, D HT,(k,j) is the dry deposition factor of tritiated hydrogen in sub-area k at the jth time step, A k is the area of ​​subregion k; k oxi is the ratio of tritiated hydrogen oxidized to tritiated water in soil; j is the re-evaporation ratio of tritiated water at the jth time step.

[0105] After tritiated hydrogen is deposited in the soil, part of it will be oxidized to tritiated water, which will then re-evaporate into the atmosphere. By calculating the dry deposition factor, oxidation ratio, and re-evaporation ratio of tritiated hydrogen, the re-evaporation factor of tritiated hydrogen can be obtained. The specific steps are as follows:

[0106] Step 1: Determine the computational domain and divide it into k sub-regions, and obtain the area A of each sub-region k Step 2: Calculate the dry deposition factor DP of tritiated hydrogen in each sub-area at the jth time step HT,(k,j) Step 3: Obtain the oxidation ratio k of tritiated hydrogen oxi and the re-evaporation ratio of tritiated water re j Step 4: Substitute the above values ​​into formula (5) to calculate the re-evaporation factor RE of tritiated hydrogen in each sub-area: HT,(k,j) .

[0107] In this embodiment, the re-evaporation factor of tritiated hydrogen can be accurately calculated by combining the dry deposition factor of tritiated hydrogen, the oxidation ratio and the re-evaporation ratio of tritiated water through formula (5). This provides an important basis for evaluating the dynamic behavior of tritium in the environment, helps to understand the transformation process of tritiated hydrogen under different regional and time conditions, and provides scientific support for environmental monitoring and risk assessment.

[0108] By dividing the computational domain into multiple sub-regions, the deposition and evaporation of tritiated hydrogen in different regions can be evaluated more accurately.

[0109] In one example, if Figure 2 The computational domain shown can be divided as follows:

[0110] By dividing the area into several concentric rings and sectors, it is possible to ensure uniform conditions within each sub-area, thereby more accurately calculating the contribution of the re-evaporation effect of HTO (tritiated water) in the soil to the tritium concentration at the evaluation point (calculation point).

[0111] Specifically, the position where the tritium concentration in the air needs to be calculated is taken as the center of the circle; the area is evenly divided into 16 sectors, each with an angle of 22.5°; several concentric rings are divided from small to large according to the radius to form multiple sub-areas (sectors). Ensure that the meteorological conditions, soil physical and chemical properties, and the concentration of tritiated hydride in each sub-area are uniform. The gaseous tritium concentration of each sub-area at each time step can be calculated with a time step of 1 hour.

[0112] Optionally, the re-evaporation factor of the tritiated water is obtained according to the dry and wet deposition factors of the tritiated water and the re-evaporation ratio of the tritiated water, which may specifically include:

[0113] The reevaporation factor is calculated by the following formula (6):

[0114] REHTO,(k,j) =(DP HTO,(k,j) +DW k,j )×A k × j (6)

[0115] Among them, RE HTO,(k,j) is the re-evaporation factor of tritiated water in sub-area k at the jth time step, DP HTO,(k,j) is the dry deposition factor of tritiated water in subarea k at the jth time step, DW k,j is the wet deposition factor of tritiated water in subarea k at the jth time step, A k is the area of ​​subregion k; re j is the re-evaporation ratio of tritiated water at the jth time step.

[0116] Specifically, the re-evaporation factor of tritiated water refers to the amount of tritiated water that is directly deposited from the air to the surface or soil and evaporates from the surface or soil to the atmosphere. The re-evaporation factor of tritiated water can be obtained by calculating the dry and wet deposition factors and re-evaporation ratio of tritiated water.

[0117] Optionally, the above step 104 may specifically include the following steps:

[0118] The re-evaporation diffusion factor of gaseous tritium is calculated by the following formulas (7) to (8):

[0119] (x re,k / Q) j =2.032×RE k,j / (σ z,j ×u j × k ) (7)

[0120] (x re / Q) j =∑ k (x re,k / Q) j (8)

[0121] Among them, (χ re,k / Q) j is the reevaporation diffusion factor of sub-area k at the jth unit time to the calculation point, which reflects the diffusion capacity of gaseous tritium from the sub-area to the calculation point; RE k,j is the reevaporation factor; (χ re / Q) j is the re-evaporation diffusion factor of the calculation point at time j (i.e., the total re-evaporation diffusion factor of the calculation point), x k is the distance from the center point of sub-region k to the corresponding calculation point.

[0122] Specifically, formula (7) and formula (8), combined with meteorological data, environmental parameters and re-evaporation factors, can accurately calculate the re-evaporation diffusion factor of gaseous tritium. This calculation provides an important basis for evaluating the diffusion behavior of tritium in the environment, helps to understand the transformation process of tritium under different regional and time conditions, and provides scientific support for environmental monitoring and risk assessment.

[0123] Optionally, the above step 105 specifically includes:

[0124] The concentration of gaseous tritium emitted from nuclear facilities is calculated by the following formula (9):

[0125]

[0126] Among them, (χ T / Q) is the ratio of the concentration of gaseous tritium at the calculation point at time j to the gaseous tritium emission rate, (χ / Q) is the atmospheric diffusion factor, t reem is the time for tritiated water to re-evaporate, (χ re / Q) j is the re-evaporation diffusion factor of the calculation point at time j.

[0127] In environmental monitoring of nuclear facilities, the concentration of gaseous tritium is an important indicator for assessing its impact on the environment and public health. By adding the atmospheric diffusion factor and the re-evaporation diffusion factor, the total concentration of gaseous tritium emitted by nuclear facilities can be obtained. Specifically, by adding the atmospheric diffusion factor and the re-evaporation diffusion factor, the concentration of gaseous tritium in the environment can be comprehensively assessed, and the changes in gaseous tritium at different time steps are further considered, which can more accurately reflect the behavior of tritium in the environment.

[0128] The method for calculating the concentration of gaseous tritium emitted by nuclear facilities provided in the embodiment of the present application systematically obtains the emission parameters, meteorological data and environmental parameters of the nuclear facilities, and uses the atmospheric diffusion model and the deposition and re-evaporation model to accurately calculate the environmental concentration of gaseous tritium. It fully considers the physical and chemical behavior of gaseous tritium in the environment, including atmospheric diffusion, dry and wet deposition, soil oxidation, re-evaporation and other processes. Each claim provides a detailed description and formula derivation for a specific calculation link, ensuring the scientific nature and operability of the method. .

[0129] In order to facilitate the understanding of the concentration calculation method of gaseous tritium emitted by nuclear facilities provided in this embodiment, a practical application description of the above method is provided here, combined with the meteorological and soil conditions of typical plant sites in my country. It is assumed that 3.57×1014Bq of gaseous tritium is released under long-term release conditions of nuclear facilities, HT and HTO each account for 50%, the release height is 60m, and the release time is 1 year.

[0130] like Figure 3 For details, see the following example:

[0131] 1. Calculation of atmospheric dispersion factor and dry and wet deposition factor

[0132] First, based on the meteorological conditions and data around the nuclear facility (including three-dimensional joint frequency, four-dimensional joint frequency, atmospheric diffusion parameters, etc.), the atmospheric diffusion factor, dry deposition factor and wet deposition factor of tritiated hydrogen at different distances in all directions centered on the discharge port are calculated. The specific calculation model is as follows:

[0133] (1) Atmospheric dispersion factor

[0134] Long-term release:

[0135]

[0136] Short-term release:

[0137]

[0138] Where: (χ / Q) is the primary atmospheric diffusion factor of tritiated hydride, s / m 3 ; x is the downwind distance from the release point; Q is the release rate of tritiated hydride, Bq / s; u is the wind speed at the release height, m / s; y is the crosswind distance, m; z is the height of the calculation point, m; H is the effective height of the release point, m; σ y , σ z They are the horizontal and vertical diffusion parameters, m, respectively, which are related to the atmospheric stability of the environment and the distance to the release point. In engineering practice, this parameter is obtained through atmospheric diffusion experiments.

[0139] The atmospheric diffusion factor (χ / Q) in the above formula (1) and formula (2) is determined based on the Gaussian plume model and is used to characterize the spatial distribution of pollutants in the atmosphere.

[0140] (2) Dry deposition factor

[0141] DP=(χ / Q)×V d (3)

[0142] Where: DP is the dry deposition factor of tritiated hydrogen, m -2 ; V d is the dry deposition rate, m / s, which is usually obtained by combining engineering experience and the environmental conditions around the nuclear facility.

[0143] The dry deposition factor (DP) is used to characterize the process of gaseous pollutants being directly deposited on the surface due to gravity, adhesion, etc.

[0144] (3) Wet deposition factor

[0145]

[0146] Where: DW is the wet deposition factor of tritiated hydrogen, m -2 ; L is rainfall, mm / h; a and b are rainfall flushing coefficients, a is in 1 / s, b is dimensionless, and rainfall flushing coefficients are usually obtained by combining engineering experience and environmental conditions around nuclear facilities. The wet deposition factor (DW) is used to characterize the process of pollutants being washed and deposited with precipitation.

[0147] The atmospheric diffusion factor calculated according to the above formula (2) is shown in the following Table 1.

[0148] Table 1: Primary diffusion factor of tritiated hydrogen (χ / Q) (centered at the release point)

[0149] Unit: s / m 3

[0150]

[0151] In the calculation, the dry deposition rate of HT is 5×10-4m / s; the dry deposition rate of HTO is 1×10-2, and the wet deposition flushing coefficient of HTO is a=1.2×10-4 / s, b=0.8. The dry deposition rate of HT and the dry and wet deposition rates of HTO are calculated according to formulas (3) to (4) and are shown in Tables 2 to 4.

[0152] Table 2: HT dry deposition factor (centered on the release point) Unit: m -2

[0153]

[0154]

[0155] Table 3: HTO dry deposition factor (centered on the release point) Unit: m -2

[0156]

[0157]

[0158] Table 4: HTO wet deposition factor (centered on the release point) Unit: m -2

[0159]

[0160]

[0161] 2. Calculation of reevaporation factor

[0162] Furthermore, the area is divided into several concentric rings according to the radius to form multiple sub-areas (sectors) to ensure uniform conditions in each sub-area. For details, see Figure 2 .

[0163] Specifically, the location where the tritium concentration in the air needs to be calculated is determined, and the location is used as the center of the circle to evenly divide it into 16 sectors (each 22.5°), and several sectors (hereinafter referred to as sub-areas) are divided according to the radius from small to large. The time step is 1 hour, and the meteorological conditions, soil physical and chemical properties, and the concentration of tritiated hydrides in each sub-area under each time step are uniform. The contribution of the HTO re-evaporation effect in the soil in these sub-areas to the tritium concentration at the evaluation point is calculated. The process of HTO in the soil re-evaporating and diffusing is as follows: Figure 2 The process of HTO re-evaporation and diffusion in the soil is shown.

[0164] The process of re-evaporation of tritiated hydrogen deposited in the soil in sub-area k satisfies the following model:

[0165] (1) For HT, since it is insoluble in water, only its dry deposition effect is considered. At the same time, after HT is deposited in the soil, it will be converted into HTO through the oxidation of the soil and then evaporate:

[0166] RE k,j =DP k,j ×A k ×k oxi × j (5)

[0167] (2) For HTO, it will be deposited into the soil under the action of dry deposition and wet deposition, and then evaporate again:

[0168] RE k,j =(DP k,j +DW k,j )×A k × j (6)

[0169] Where: RE k,j is the re-evaporation factor of tritiated hydrogen in sub-area k at the jth hour, dimensionless; DP k,j is the dry deposition factor of tritiated hydrogen in sub-area k at the jth hour, m -2 ;DW k,j is the wet deposition factor of tritiated hydrogen in sub-area k at the jth hour, m -2 ; A k is the area of ​​subregion k, m 2 ;k oxi is the ratio of HT oxidation in soil; j is the re-evaporation ratio of HTO at the jth hour.

[0170] Re-evaporation process: After tritium is deposited in the soil, HT is converted into HTO due to oxidation, and HTO returns to the atmosphere through evaporation. The re-evaporation effect of the soil is equivalent to a surface source, which affects the tritium concentration in the air.

[0171] The dry deposition rate of HT and the dry and wet deposition rates of HTO calculated according to the above formulas (3) to (4) are shown in Tables 2 to 4 above.

[0172] 3. Re-evaporation HTO dispersion calculation

[0173] Furthermore, the re-evaporated HTO in each sub-area will serve as a ground release source and contribute to the tritiated hydride diffusion factor of the evaluation point under the action of atmospheric diffusion. When dealing with ground surface sources, the Gaussian model needs to be improved to a certain extent. The re-evaporated HTO is a continuous surface source, and its diffusion process is similar to that of a point source, but the source intensity distribution is different. Its law satisfies the following formula (7):

[0174] (x re,k / Q) j =2.032×RE k,j / (σ z,j ×u j × k ) (7)

[0175] Where: (χ re,k / Q) j is the diffusion factor of HTO re-evaporation in sub-area k at the jth hour contributing to the evaluation point, s / m 2 ; σ z,j is the vertical diffusion parameter at the jth hour, m; u j is the wind speed at the jth hour, m / s; x k is the distance from the center of sub-area k to the evaluation point, m.

[0176] Therefore, the diffusion factor (χ re / Q) j Satisfies the following formula:

[0177]

[0178] The 500m W position of the nuclear facility was selected as the calculation point of tritium concentration. When calculating the re-evaporation effect of HTO, the radius of the ring segment from small to large is 100, 200, 500, 1000, 2000, 5000, 10000m, assuming that all HT deposited in the soil is oxidized to HTO, the re-evaporation ratio of HTO is 0.02, and the duration of the re-evaporation effect is 24h.

[0179] The secondary diffusion factors contributed by HTO reevaporation in different sub-areas centered on the calculation point are calculated according to formulas (5)-(8).

[0180] 4.2.4 Calculation of final concentration of tritiated hydrogen

[0181] Finally, calculate the final concentration of tritiated hydrogen at the point T It is the sum of the primary diffusion after release from the nuclear facility and the secondary diffusion after deposition and re-evaporation, as shown in the following formula:

[0182]

[0183] Where, t reem is the time for HTO to re-evaporate.

[0184] According to formula (9), the final atmospheric diffusion factor of tritiated hydrogen at 500 m in the W direction is the sum of the primary diffusion factor at this location and the secondary diffusion factors of each reevaporation sub-area centered at this location (see Tables 5-6). The final calculated tritiated hydrogen concentration at this location is 2.00 Bq / m 3 , where: HT concentration is 0.91Bq / m 3 , HTO concentration is 1.09Bq / m 3 ; The concentration contributed by primary diffusion is 1.81 Bq / m 3 After re-evaporation, the secondary contribution concentration is 0.19 Bq / m 3 .

[0185] Table 5 Secondary diffusion factor of HT after soil oxidation and reevaporation (χre / Q)HT (centered at the concentration calculation point)

[0186] Unit: s / m3

[0187]

[0188]

[0189] Table 6 Secondary diffusion factor (χ) of HTO re-evaporation re / Q) HTO (centered at the concentration calculation point) Unit: s / m 3

[0190]

[0191] This embodiment can calculate the concentration of tritiated hydrogen in the environment more accurately based on the meteorological and soil environmental conditions around the nuclear facility, while considering the primary diffusion of tritiated hydrogen discharged from the nuclear facility and the secondary diffusion after its deposition in the soil and re-evaporation. It can be used for the tritiated hydrogen concentration in the environment of reactor types such as fast reactors and fusion reactors with larger tritiated hydrogen storage and release under normal operation, expected operation events and accident conditions, and then calculate its radiation dose. This invention has a positive effect on the design, site selection, construction, accident consequence assessment and environmental friendliness of my country's advanced nuclear power reactor types.

[0192] Embodiment 2:

[0193] like Figure 4 As shown, this embodiment provides a concentration calculation device 400 for gaseous tritium discharged from a nuclear facility, comprising:

[0194] An acquisition module 401 is used to acquire meteorological data, environmental parameters and emission parameters of the nuclear facility, wherein the environmental parameters are parameters of the external environment of the nuclear facility;

[0195] A first calculation module 402, connected to the acquisition module, is used to determine the atmospheric diffusion factor of the gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters, wherein the atmospheric diffusion factor is the ratio of the concentration of the gaseous tritium emitted by the nuclear facility after diffusion in the atmosphere to the emission rate of the gaseous tritium;

[0196] A second calculation module 403, connected to the acquisition module, is used to determine the re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters, wherein the re-evaporation factor is the amount of the gaseous tritium deposited on the surface that re-enters the atmosphere through the re-evaporation process;

[0197] A third calculation module 404, respectively connected to the acquisition module, the first calculation module and the second calculation module, is used to determine a re-evaporation diffusion factor of gaseous tritium based on the meteorological data, the environmental parameters and the re-evaporation factor, wherein the re-evaporation diffusion factor is a ratio of the concentration of re-evaporated gaseous tritium after diffusion in the atmosphere to the gaseous tritium emission rate;

[0198] The fourth calculation module 405 is connected to the first calculation module and the third calculation module, and is used to add the atmospheric diffusion factor and the re-evaporation diffusion factor to obtain the concentration of gaseous tritium emitted by the nuclear facility.

[0199] The concentration calculation device for gaseous tritium emitted by nuclear facilities in this embodiment takes into account the migration and transformation process of tritium in the environment, including the primary atmospheric diffusion and the secondary diffusion process of re-evaporation after deposition. By incorporating the re-evaporation contribution into the concentration calculation, the impact of tritium emitted by nuclear facilities on the surrounding environment and public health can be more accurately assessed, thereby improving the accuracy and reliability of environmental impact assessment.

[0200] Optionally, the first calculation module 402 includes:

[0201] The first calculation unit is used to calculate the atmospheric dispersion factor by the following formula (1) when the nuclear facility emits gaseous tritium for a long time:

[0202]

[0203] The second calculation unit is used to calculate the atmospheric dispersion factor by the following formula (2) when the emission of gaseous tritium by the nuclear facility is short-term emission:

[0204]

[0205] Where (χ / Q) is the primary atmospheric diffusion factor of gaseous tritium, x is the downwind distance from the calculation point to the release point, the calculation point is a location used to monitor or evaluate the concentration of tritium at a specific location, Q is the release rate of gaseous tritium; u is the wind speed at the release height, y is the crosswind distance, z is the height of the calculation point, H is the effective height of the release point, σ y , σ z are the horizontal and vertical diffusion parameters respectively.

[0206] Optionally, the gaseous tritium includes tritiated hydrogen and tritiated water, and the second calculation module 403 includes:

[0207] A third calculation unit is used to determine the deposition amount of gaseous tritium according to the deposition effect based on the atmospheric diffusion factor, the deposition property of gaseous tritium, and the meteorological data. The deposition amount of gaseous tritium includes a dry deposition factor of tritiated hydrogen and dry and wet deposition factors of tritiated water;

[0208] a fourth calculation unit, for obtaining a reevaporation factor of tritiated hydrogen according to the dry deposition factor of tritiated hydrogen, the oxidation ratio and the reevaporation ratio of tritiated water, wherein the oxidation ratio is a ratio of tritiated hydrogen oxidized to tritiated water in the soil;

[0209] a fifth calculation unit, connected to the third calculation unit, for obtaining a reevaporation factor of the tritiated water according to the dry and wet deposition factors of the tritiated water and the reevaporation ratio of the tritiated water,

[0210] The re-evaporation factor of gaseous tritium includes the re-evaporation factor of tritiated hydrogen and the re-evaporation factor of tritiated water.

[0211] Optionally, the deposition properties of gaseous tritium include a dry deposition rate of tritiated hydrogen and a dry deposition rate of tritiated water, and the meteorological data include a rainfall washoff coefficient, rainfall, and wind speed,

[0212] The third computing unit comprises:

[0213] The first calculation subunit is used to obtain a dry deposition factor according to the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor, and the dry deposition factor is used to characterize the amount of tritiated hydrogen directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion;

[0214] The second calculation subunit is used to obtain the dry deposition factor of tritiated water according to the dry deposition rate of tritiated water and the atmospheric diffusion factor. The dry deposition factor of tritiated water is used to characterize the amount of tritiated water directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion;

[0215] The third calculation subunit is used to obtain the wet deposition factor of tritiated water according to the rainfall, the rainfall washing coefficient and the wind speed. The wet deposition factor of tritiated water is used to characterize the amount of tritiated water washed out of the atmosphere by precipitation processes such as rainfall or snowfall and deposited on the surface.

[0216] Among them, the deposition factor of gaseous tritium includes the dry deposition factor of tritiated water, the dry deposition factor of tritiated water and the wet deposition factor of tritiated water.

[0217] Embodiment 3: This embodiment provides a nuclear facility safety assessment method, the method comprising:

[0218] According to the method for calculating the concentration of gaseous tritium emitted by a nuclear facility provided in any of the above embodiments, the concentration of gaseous tritium corresponding to a plurality of calculation points in the external environment of the nuclear facility is calculated;

[0219] The safety assessment of nuclear facilities is carried out based on the concentration of gaseous tritium corresponding to multiple calculation points.

[0220] The specific steps may include:

[0221] Step 1: According to the above-mentioned method for calculating the concentration of gaseous tritium, determine multiple calculation points in the external environment of the nuclear facility. These calculation points can be different locations around the nuclear facility, aiming to comprehensively evaluate the distribution of gaseous tritium.

[0222] Step 2: Conduct safety assessment of nuclear facilities based on the gaseous tritium concentrations corresponding to multiple calculation points.

[0223] The assessment process may include the following aspects:

[0224] Risk assessment: Evaluate the potential risks to public health and the environment from nuclear facilities by comparing the calculated gaseous tritium concentration with safety standards (such as national or international standards for the discharge of radioactive materials).

[0225] Trend analysis: Analyze the changing trend of gaseous tritium concentration to determine whether there are abnormal conditions or potential safety hazards.

[0226] Emergency response: Based on the assessment results, formulate appropriate emergency response measures to deal with possible gaseous tritium leakage or excessive concentration incidents.

[0227] The nuclear facility safety assessment method provided in this embodiment can comprehensively assess the safety of nuclear facilities by calculating the gaseous tritium concentration at multiple calculation points in the external environment of nuclear facilities. This method combines the dynamic calculation of gaseous tritium concentration with environmental monitoring, provides a scientific basis for the safety management and risk control of nuclear facilities, and helps protect public health and environmental safety.

[0228] Embodiment 3: This embodiment provides a nuclear facility safety assessment device, the device comprising:

[0229] The device for calculating the concentration of gaseous tritium emitted by a nuclear facility provided in any of the above embodiments is used to obtain the concentration of gaseous tritium corresponding to a plurality of calculation points in the external environment of the nuclear facility;

[0230] The safety assessment module is connected to the concentration calculation device and is used to perform safety assessment on the nuclear facility based on the concentration of gaseous tritium corresponding to a plurality of calculation points.

[0231] The nuclear facility safety assessment device provided in this embodiment can comprehensively assess the safety of nuclear facilities by calculating the gaseous tritium concentration at multiple calculation points in the external environment of the nuclear facility. This method combines the dynamic calculation of gaseous tritium concentration with environmental monitoring, provides a scientific basis for the safety management and risk control of nuclear facilities, and helps protect public health and environmental safety.

[0232] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0233] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0234] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0235] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable scheduling device to produce a machine so that these instructions executed by the processor of the computer or other programmable scheduling device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0236] The above are only specific implementation methods of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for calculating the concentration of gaseous tritium emitted from a nuclear facility, characterized in that: include: Acquiring meteorological data, environmental parameters and emission parameters of the nuclear facility, wherein the environmental parameters are parameters of the external environment of the nuclear facility; Determine the atmospheric diffusion factor of the gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters, wherein the atmospheric diffusion factor is the ratio of the concentration of the gaseous tritium emitted by the nuclear facility after diffusion in the atmosphere to the emission rate of the gaseous tritium; Determine a re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters, wherein the re-evaporation factor is used to characterize the amount of gaseous tritium deposited on the surface that re-enters the atmosphere through the re-evaporation process; Determining a re-evaporation diffusion factor of gaseous tritium based on the meteorological data, environmental parameters and the re-evaporation factor, wherein the re-evaporation diffusion factor is a ratio of a concentration of re-evaporated gaseous tritium after diffusion in the atmosphere to a gaseous tritium emission rate; Based on the atmospheric diffusion factor and the re-evaporation diffusion factor, the concentration of gaseous tritium emitted by the nuclear facility is obtained.

2. The method according to claim 1, characterized in that Determining the atmospheric dispersion factor of gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters specifically includes: In the case where the nuclear facility emits gaseous tritium for a long time, the atmospheric dispersion factor is calculated by the following formula (1): When the emission of gaseous tritium from the nuclear facility is short-term, the atmospheric dispersion factor is calculated by the following formula (2): Where (χ / Q) is the first atmospheric diffusion factor of gaseous tritium, x is the downwind distance from the calculation point to the release point, the calculation point is a location used to monitor or evaluate the concentration of tritium at a specific location, Q is the release rate of gaseous tritium; u is the wind speed at the release height, y is the crosswind distance, z is the height of the calculation point, H is the effective height of the release point, σ y , σ z are the horizontal and vertical diffusion parameters, respectively; The obtaining, based on the atmospheric diffusion factor and the re-evaporation diffusion factor, the concentration of gaseous tritium emitted by the nuclear facility specifically includes: The atmospheric diffusion factor and the re-evaporation diffusion factor are added together to obtain the concentration of gaseous tritium emitted by the nuclear facility.

3. The method according to claim 1, characterized in that The gaseous tritium includes tritiated hydrogen and tritiated water. Determining the re-evaporation factor of the discharged gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters specifically includes: Based on the atmospheric diffusion factor, the deposition properties of gaseous tritium, and meteorological data, a deposition factor of gaseous tritium is determined according to the deposition effect, wherein the deposition factor of gaseous tritium includes a deposition factor of tritiated hydrogen and a deposition factor of tritiated water; The re-evaporation factor of the tritiated hydrogen is obtained according to the deposition factor of the tritiated hydrogen, the oxidation ratio and the re-evaporation ratio of the tritiated water, wherein the oxidation ratio is the ratio of tritiated hydrogen oxidized to tritiated water in the soil; According to the deposition factor of the tritiated water and the re-evaporation ratio of the tritiated water, the re-evaporation factor of the tritiated water is obtained. Wherein, the re-evaporation factor of the gaseous tritium includes the re-evaporation factor of the tritiated hydrogen and the re-evaporation factor of tritiated water.

4. The method according to claim 3, characterized in that The deposition properties of the gaseous tritium include the dry deposition factor of tritiated hydrogen and the dry and wet deposition factors of tritiated water, and the meteorological data include the rainfall flushing coefficient, rainfall and wind speed. The method of determining the deposition factor of gaseous tritium based on the atmospheric diffusion factor, the deposition properties of gaseous tritium, and meteorological data according to the deposition effect specifically includes: According to the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor, a dry deposition factor of tritiated hydrogen is obtained, wherein the dry deposition factor of tritiated hydrogen is used to characterize the amount of tritiated hydrogen directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion; According to the dry deposition rate of tritiated water and the atmospheric diffusion factor, a dry deposition factor of tritiated water is obtained, wherein the dry deposition factor of tritiated water is used to characterize the amount of tritiated water directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion; According to the rainfall, the rainfall washing coefficient and the wind speed, the wet deposition factor of the tritiated water is obtained, and the wet deposition factor of the tritiated water is used to characterize the amount of tritiated water washed out of the atmosphere by precipitation processes such as rain or snow and deposited on the surface. The deposition factor of the gaseous tritium includes the dry deposition factor of the tritiated water, the dry deposition factor of the tritiated water and the wet deposition factor of the tritiated water.

5. The method according to claim 4, characterized in that: The step of obtaining the dry deposition factor of tritiated hydrogen or tritiated water according to the dry deposition rate of tritiated hydrogen or tritiated water and the atmospheric diffusion factor specifically comprises: The dry deposition factor is calculated by formula (3): DP=(χ / Q)×V d (3) Wherein, DP is the dry deposition factor of the tritiated hydrogen or tritiated water, (χ / Q) is the atmospheric diffusion factor of the gaseous tritium, V d is the dry deposition rate of tritiated hydrogen or tritiated water.

6. The method according to claim 4, characterized in that The wet deposition factor of tritiated water is obtained according to the rainfall, rainfall flushing coefficient and wind speed, including: The wet deposition factor of the tritiated water is calculated by formula (4): Wherein, DW is the wet deposition factor of the tritiated water, u is the wind speed at the release height, x is the downwind distance of the calculation point from the release point, the calculation point is a location used to monitor or evaluate the concentration of tritium at a specific location, a and b are rainfall flushing coefficients, a is in 1 / s, b is dimensionless, and L is the rainfall.

7. The method according to claim 3, characterized in that: The re-evaporation factor of the tritiated hydrogen is obtained according to the dry deposition factor of the tritiated hydrogen, the oxidation ratio and the re-evaporation ratio of the tritiated water, specifically comprising: Determine a calculation domain, the calculation domain is a circular area with the calculation point as the origin and a radius as a preset distance, and the calculation domain includes k sub-areas; The re-evaporation factor of the tritiated hydrogen is calculated by the following formula (5): RE HT,(k,j) =DP HT,(k,j) ×A k ×k oxi ×re j (5) Among them, RE HT，(k,j) is the re-evaporation factor of tritiated hydrogen in sub-area k at the jth time step, DP HT,(k,j) is the dry deposition factor of tritiated hydrogen in sub-area k at the jth time step, A k is the area of ​​subregion k; k oxi is the ratio of tritiated hydrogen oxidized to tritiated water in soil; j is the re-evaporation ratio of tritiated water at the jth time step.

8. The method according to claim 3, characterized in that: The re-evaporation factor of the tritiated water is obtained according to the dry and wet deposition factors of the tritiated water and the re-evaporation ratio of the tritiated water, specifically comprising: The re-evaporation factor of the tritiated water is calculated by the following formula (6): RE HTO,(k,j) =(DP HTO,(k,j) +DW k,j )×A k ×re j (6) Among them, RE HTO,(k,j) is the re-evaporation factor of tritiated water in sub-area k at the jth time step, DP HTO，(k,j) is the dry deposition factor of tritiated water in subarea k at the jth time step, DW k,j is the wet deposition factor of tritiated water in subarea k at the jth time step, A k is the area of ​​subregion k; re j is the re-evaporation ratio of tritiated water at the jth time step.

9. The method according to claim 3, characterized in that: Determining the reevaporation diffusion factor of gaseous tritium based on the meteorological data, environmental parameters and the reevaporation factor specifically includes: The re-evaporation diffusion factor of the gaseous tritium is calculated by the following formula (7) to formula (8): (x re,k / Q) j =2.032×RE k,j / (s z,j ×u j ×x k ) (7) (x re / Q) j =∑ k (x re,k / Q) j (8) Among them, (χ re,k / Q) j is the reevaporation factor of sub-area k at the jth unit time for the reevaporation diffusion factor of the calculation point, RE k,j is the re-evaporation factor, (χ re / Q) j is the re-evaporation diffusion factor of the calculation point at time j, x k is the downwind distance from the center point of sub-area k to the calculation point.

10. The method according to claim 1, characterized in that The concentration of gaseous tritium emitted from the nuclear facility is obtained by adding the atmospheric dispersion factor and the re-evaporation dispersion factor, specifically including: The concentration of gaseous tritium emitted by the nuclear facility is calculated by the following formula (9): Among them, the (x T / Q) is the ratio of the concentration of gaseous tritium at the calculation point at time j to the gaseous tritium emission rate, (χ / Q) is the atmospheric diffusion factor, t reem is the time for tritiated water to re-evaporate, (χ re / Q) j is the re-evaporation diffusion factor of the calculation point at time j.

11. A device for calculating the concentration of gaseous tritium emitted from a nuclear facility, characterized in that: The device comprises: An acquisition module, used to acquire meteorological data, environmental parameters and emission parameters of the nuclear facility, wherein the environmental parameters are parameters of the external environment of the nuclear facility; A first calculation module, connected to the acquisition module, is used to determine the atmospheric diffusion factor of the gaseous tritium emitted by the nuclear facility based on the meteorological data, environmental parameters and emission parameters, wherein the atmospheric diffusion factor is the ratio of the concentration of the gaseous tritium emitted by the nuclear facility after diffusion in the atmosphere to the emission rate of the gaseous tritium; A second calculation module, connected to the acquisition module, is used to determine the re-evaporation factor of the emitted gaseous tritium based on the atmospheric diffusion factor, the deposition properties of the gaseous tritium, meteorological data and environmental parameters, wherein the re-evaporation factor is the amount of the gaseous tritium deposited on the surface that re-enters the atmosphere through the re-evaporation process; a third calculation module, respectively connected to the acquisition module, the first calculation module and the second calculation module, for determining a re-evaporation diffusion factor of gaseous tritium based on the meteorological data, the environmental parameters and the re-evaporation factor, wherein the re-evaporation diffusion factor is a ratio of the concentration of the re-evaporated gaseous tritium after diffusion in the atmosphere to the gaseous tritium emission rate; The fourth calculation module is connected to the first calculation module and the third calculation module, and is used to obtain the concentration of gaseous tritium emitted by the nuclear facility based on the atmospheric diffusion factor and the re-evaporation diffusion factor.

12. The device according to claim 11, characterized in that The first calculation module includes: The first calculation unit is used to calculate the atmospheric dispersion factor by the following formula (1) when the nuclear facility emits gaseous tritium for a long time: The second calculation unit is used to calculate the atmospheric dispersion factor by the following formula (2) when the emission of gaseous tritium by the nuclear facility is short-term emission: Where (χ / Q) is the primary atmospheric diffusion factor of gaseous tritium, x is the downwind distance from the calculation point to the release point, the calculation point is a location used to monitor or evaluate the concentration of tritium at a specific location, Q is the release rate of gaseous tritium; u is the wind speed at the release height, y is the crosswind distance, z is the height of the calculation point, H is the effective height of the release point, σ y , σ z are the horizontal and vertical diffusion parameters respectively.

13. The device according to claim 11, characterized in that Gaseous tritium includes tritiated hydrogen and tritiated water, and the second calculation module includes: A third calculation unit is used to determine a deposition factor of gaseous tritium according to the deposition effect based on the atmospheric dispersion factor, the deposition property of gaseous tritium, and the meteorological data. The deposition factor of gaseous tritium includes a dry deposition factor of tritiated hydrogen and dry and wet deposition factors of tritiated water. a fourth calculation unit, for obtaining a reevaporation factor of tritiated hydrogen according to the dry deposition factor of tritiated hydrogen, the oxidation ratio and the reevaporation ratio of tritiated water, wherein the oxidation ratio is a ratio of tritiated hydrogen oxidized to tritiated water in the soil; a fifth calculation unit, connected to the third calculation unit, for obtaining a reevaporation factor of the tritiated water according to the dry and wet deposition factors of the tritiated water and the reevaporation ratio of the tritiated water, The re-evaporation factor of gaseous tritium includes the re-evaporation factor of tritiated hydrogen and the re-evaporation factor of tritiated water.

14. The device according to claim 11, characterized in that The deposition properties of gaseous tritium include the dry deposition rate of tritiated hydrogen and the dry deposition rate of tritiated water, and the meteorological data include the rainfall washoff coefficient, rainfall and wind speed. The third computing unit comprises: The first calculation subunit is used to obtain a dry deposition factor of tritiated hydrogen according to the dry deposition rate of tritiated hydrogen and the atmospheric diffusion factor. The dry deposition factor of tritiated hydrogen is used to characterize the amount of tritiated hydrogen directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion; The second calculation subunit is used to obtain the dry deposition factor of tritiated water according to the dry deposition rate of tritiated water and the atmospheric diffusion factor. The dry deposition factor of tritiated water is used to characterize the amount of tritiated water directly deposited from the atmosphere to the surface through mechanisms such as gravity deposition and turbulent diffusion; The third calculation subunit is used to obtain the wet deposition factor of tritiated water according to the rainfall, the rainfall washing coefficient and the wind speed. The wet deposition factor of tritiated water is used to characterize the amount of tritiated water washed out of the atmosphere by precipitation processes such as rainfall or snowfall and deposited on the surface. The deposition factor of the gaseous tritium includes the dry deposition factor of the tritiated water, the dry deposition factor of the tritiated water and the wet deposition factor of the tritiated water.

15. A nuclear facility safety assessment method, characterized in that: The method comprises: The method for calculating the concentration of gaseous tritium emitted by a nuclear facility according to any one of claims 1 to 10 obtains the concentration of gaseous tritium corresponding to a plurality of calculation points in the external environment of the nuclear facility; Based on the concentrations of gaseous tritium corresponding to the multiple calculation points, a safety assessment is performed on the nuclear facility.

16. A nuclear facility safety assessment device, characterized in that: include: The device for calculating the concentration of gaseous tritium emitted by a nuclear facility as claimed in any one of claims 11 to 14, which is used to obtain the concentration of gaseous tritium corresponding to multiple calculation points in the external environment of the nuclear facility; A safety assessment module is connected to the concentration calculation device and is used to perform safety assessment on the nuclear facility based on the concentration of gaseous tritium corresponding to the multiple calculation points.

Images