A method, device and storage medium for dividing nuclear power plant ingestion emergency plan areas

Abstract

The present invention relates to a method for dividing the ingestion emergency plan area of ​​a nuclear power plant, which belongs to the field of nuclear power safety. In order to solve the problem of inadequate division of the ingestion emergency plan area and insufficient analysis, the present invention considers the hourly meteorological conditions of the plant site in the past year for the accident sequence release class given by the secondary PSA, obtains the corresponding meteorological data group according to the specified meteorological data sampling method, combines the frequency of occurrence of the accident sequence, calculates the food contamination level of each nuclide at different distances around the nuclear power plant under each meteorological data group, and finally combines the dose limit and the frequency limit to determine the scope of the ingestion emergency plan area of ​​the nuclear power plant. The method for dividing the ingestion emergency plan area of ​​a nuclear power plant disclosed by the present invention is adopted, and the index analysis is comprehensive and sufficient, the calculation process is simplified, the calculation efficiency is improved, and the scope of the ingestion emergency plan area can be accurately divided.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear power safety technology, and in particular relates to a method, a device and a storage medium for dividing ingestion emergency plan areas of a nuclear power plant. Background Art

[0002] In the early stage of a nuclear accident, direct external exposure to radioactive plumes and internal exposure to personnel through inhalation are the main routes of contamination. However, in the later stage of the accident, as the radioactive plume settles, the sea and soil in the nearby areas will be threatened. Due to the influence of weathering and the transfer of radioactive nuclides to the roots of crops through the soil, ingestion of contaminated food and water will cause ingestion exposure, and the ingestion exposure route will become the main exposure route.

[0003] The ingestion emergency planning area is an emergency planning area established for ingestion exposure pathways, and the scope of the ingestion emergency planning area is considered during the emergency planning stage. The division basis of the ingestion emergency planning area of ​​a nuclear power plant is clearly defined in the standard GB / T 17680.1, which requires that outside the ingestion emergency planning area, the contamination level of food and drinking water caused by most severe accident sequences should not exceed the general action level for food and drinking water specified in the standard GB18871.

[0004] In the practice of dividing the ingestion emergency plan area of ​​nuclear power plants, most of the serious accident sequences are selected differently, and deterministic source items are often selected for subsequent calculations, resulting in the over-large division of the emergency plan area and limited practicality. With the in-depth study of source items, nuclear power plants at home and abroad have gradually carried out secondary probabilistic safety analysis work, considering the impact of accidents with low frequency but serious consequences. At present, my country's nuclear safety regulations require that the design must fully consider the results of deterministic safety analysis and probabilistic safety analysis; internationally, such as the IAEA's design safety regulations, the US URD and European EUR and the US Reactor Regulatory Procedure ROP and other regulatory standards, all encourage the application of probabilistic safety analysis PSA technology to optimize the design and operation of nuclear power plants. Therefore, considering probabilistic safety factors when dividing the ingestion emergency plan area of ​​nuclear power plants is a mandatory requirement of domestic and foreign standards. Summary of the invention

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method, device and storage medium for dividing the ingestion emergency plan area of ​​a nuclear power plant, extracting a meteorological data group through meteorological conditions, and dividing the ingestion emergency plan area of ​​the nuclear power plant in combination with release type analysis of food contamination level, accident sequence occurrence frequency and frequency limit.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a method for dividing the ingestion emergency plan area of ​​a nuclear power plant, the method comprising the following steps:

[0007] S1. Consider the hourly meteorological conditions of the plant site in the past year and obtain the corresponding meteorological data group according to the specified meteorological data sampling method;

[0008] S2. Establishing an atmospheric diffusion model for each meteorological data group, and calculating the food contamination level of each nuclide at different distances around the nuclear power plant under each meteorological data group in combination with the release amount of each nuclide in the release category;

[0009] S3. Combined with the frequency of occurrence of accident sequences, calculate the food contamination level caused by each nuclide after weighting the secondary PSA source term at each distance, calculate the distance at which the food contamination level at each distance exceeds the specified general action level under the specified probability level, and combine with the general action level limit to give the frequency of exceeding the specified general action level limit at each distance;

[0010] S4. Determine the scope of the ingestion emergency plan area of ​​the nuclear power plant in combination with the frequency limit.

[0011] Further, step S1 includes setting the number of release categories of the secondary PSA source term, and setting the stockpile and release share of each nuclide for any of the secondary PSA accident sequences.

[0012] Furthermore, the meteorological data sampling method specified in step S1 includes random sampling or stratified sampling.

[0013] Further, step S2 includes the following sub-steps:

[0014] S21. For any nuclide i, based on a set of meteorological data s obtained by the sampling method and the atmospheric diffusion model, calculate the near-ground time-integrated air concentration of the radionuclide at different distances from the accident release point;

[0015] S22, considering the dry and wet deposition process of radionuclides, calculating the ground deposition concentration of the radionuclides after taking into account the deposition effect;

[0016] S23. Considering the dynamic migration process of radioactive nuclides in the food chain after deposition, the preset food chain model is used to calculate the radionuclide activity concentration corresponding to the radioactive deposition per unit area;

[0017] S24. Calculate the food contamination level caused by radionuclides in the food under the meteorological data conditions based on the ground or leaf surface deposition concentration factor;

[0018] S25. For other nuclides, repeat steps S21-S24 to calculate the food contamination level of each nuclide at different distances under the meteorological data;

[0019] S26. For other meteorological data, repeat steps S21-S25 to count the food contamination levels of nuclide i at specified meteorological probability levels at n different distances.

[0020] Furthermore, the preset food chain model in step S23 is a semi-dynamic food chain model.

[0021] Further, step S3 includes the following sub-steps:

[0022] S31. For each nuclide, rank the activity concentration of the nuclide under various meteorological data conditions from large to small, and calculate the probability level of the nuclide contamination level exceeding the general action level for food at different distances;

[0023] S32. For other accident sequences, repeat steps S21-S26 to count the food contamination level Qrin of nuclide i under each accident release type at n different distances and at the specified meteorological probability level;

[0024] S32. Consider the frequency of accidents and calculate the weighted values ​​of the food contamination levels of each nuclide at the specified meteorological probability level at different distances; consider the frequency of accidents and calculate the weighted values ​​of the food contamination levels of each nuclide at different distances that exceed the meteorological probability level of the general action level for food.

[0025] Further, step S4 includes comparing the weighted value of the food contamination level of each nuclide at the specified meteorological probability level at different distances with the general action level for food to obtain the distance exceeding the general action level; comparing the weighted value exceeding the general action level for food with the specified probability level limit to obtain the distance value that meets the specified probability level, and further determining the scope of the ingestion emergency plan area.

[0026] Furthermore, the method also includes the step of calculating the pollution level of large water bodies within the regional scope based on the scope of the ingestion emergency plan area.

[0027] A nuclear power plant ingestion emergency plan area division device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the nuclear power plant ingestion emergency plan area division method and its optional implementation methods when executing the computer program.

[0028] A storage medium stores a computer program, wherein the computer program is configured to implement a method for dividing a nuclear power plant ingestion emergency plan area and an optional implementation method thereof when executed.

[0029] The effect of the present invention is that: by adopting the method, device and storage medium for dividing the ingestion emergency plan area of ​​a nuclear power plant disclosed in the present invention, a comprehensive index analysis is performed by analyzing the diffusion range and occurrence probability of various nuclides, and the ingestion emergency plan area is accurately divided; thus, the calculation efficiency is improved.

[0030] It can be directly applied to the design and optimization of the ingestion emergency plan area division in nuclear power plants, laying a technical foundation for the implementation of the third-level probabilistic safety analysis work in nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A method flow chart of a method for dividing ingestion emergency plan areas of a nuclear power plant according to Embodiment 1 of the present invention;

[0032] Figure 2 A method flow chart of a method for dividing ingestion emergency plan areas of a nuclear power plant according to a second embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of information transmission of a nuclear power plant ingestion emergency plan area division device according to the third embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of a nuclear power plant ingestion emergency plan area division device according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0036] Embodiment 1

[0037] like Figure 1 As shown, a method for dividing the ingestion emergency plan area of ​​a nuclear power plant disclosed in the present invention comprises the following steps:

[0038] S1. Considering the hourly meteorological conditions of the factory site in the past year, obtain the corresponding meteorological data group according to the specified meteorological data sampling method.

[0039] S2. For each meteorological data group, an atmospheric diffusion model is established. Combined with the release amounts of various nuclides in the release category, the food contamination levels of each nuclide at different distances around the nuclear power plant under each meteorological data group are calculated.

[0040] S3. Combined with the frequency of accident sequence occurrence, the food contamination level caused by each nuclide after weighting the secondary PSA source term at each distance is given, and the above food contamination levels are sorted from large to small, and the distance at which the food contamination level exceeds the specified general action level at each distance under the specified probability level is given. Combined with the general action level limit given in Appendix E of GB18871-2002, the frequency level of exceeding the specified general action level limit at each distance is given.

[0041] S4. Determine the scope of the ingestion emergency planning area of ​​the nuclear power plant in combination with the frequency limit. Based on the risk-based approach, the ingestion emergency planning area of ​​the nuclear power plant is calculated by combining the general action level limit and the frequency limit.

[0042] Embodiment 2

[0043] In this embodiment, the calculation method of food contamination level is illustrated by taking the nuclear power plant as the center, the nuclides I-131 and Cs-137, and the radius of 60km. Figure 2 As shown, a method for dividing a nuclear power plant ingestion emergency plan area disclosed in the present invention, the method converges a function by a loop iteration method to complete the division of the nuclear power plant ingestion emergency plan area, comprising the following steps:

[0044] S11. Based on the hourly meteorological data of the plant site in the most recent year, a specified sampling method is used to obtain S groups of meteorological sampling data (MT1, MT2, ..., MT S ).

[0045] Sampling methods include random sampling or stratified sampling.

[0046] In this embodiment, a stratified sampling method is adopted for the hourly meteorological data throughout the year. The meteorological data are classified according to the combination of precipitation, wind direction, wind speed, and stability (about 30 categories). Four samples are randomly selected from each type of weather data (a total of about 120 groups of meteorological data) as the starting time of the accident release and the corresponding weather conditions. The meteorological data slides hour by hour from the initial time according to a duration of 6 hours.

[0047] S12. For any nuclear power plant, obtain the secondary PSA source term release category R, ​​give the stock of I-131 and Cs-137 (Ar1, Ar2, ...Ari), the frequency of accident occurrence f and the release category source term information. At least it should include: the start time of the accident release (Tb1, Tb2, ..., Tbt), the duration (T1, T2, ..., Tt), the release height of each time period (Rh1, Rh2, ..., Rht), the heat release (Tt1, Tt2, ..., Ttt), the release share of nuclides in each time period (Xrt11, Xrt12, ..., Xrt1i...; ...; Xrtt1, Xrt22, ..., Xrtti), etc. In this way, the time-divided release amount of I-131 under release category r (Qr I-131 , Bq).

[0048] QUR I-131 =Ar I-131 ·Xr I-131

[0049] S13. For any nuclide i, based on a set of meteorological data s obtained by sampling as above and an appropriate atmospheric diffusion model, calculate the near-surface time-integrated air concentrations (Cris1, Cris2, ..., Cris2) of different nuclides at different distances (d1, d2, ..., dn) from the accident release point. n ).

[0050] In this embodiment, for a set of meteorological data s, an appropriate atmospheric diffusion model is used to calculate the atmospheric diffusion factor χ / Q at different distances. s1 , χ / Q s2 , …χ / Q sn Combined with the release of I-131, the time-integrated air concentrations Cs1, Cs2, ... Csn of I-131 near the ground at different distances n under the meteorological data s are calculated. For example, the time-integrated air concentration of nuclide I-131 near the ground at distance n is:

[0051] Crsn I-131 =Qr I-131 ·χ / Q sn

[0052] S14. Considering the dry and wet deposition process of radionuclides, calculate the ground deposition concentration of radionuclides caused by deposition (Cdris1, Cdris2, ..., Cdrisn).

[0053] According to the dry and wet deposition rate F, the ground or leaf surface deposition concentrations of I-131 at different distances Cdris1, Cdris2, ..., Cdrisn are calculated under the conditions of group s meteorological data. The ground or leaf surface I-131 deposition concentration Cdrisn at distance n is:

[0054] Cdrs I-131 =Crsn I-131 ·F I-131

[0055] S15. For a specific plant site, the dynamic migration process of radioactive nuclides in the food chain after deposition is considered, and a semi-dynamic food chain model is used to calculate the radionuclide activity concentration (DS factor) corresponding to the radioactive deposition of I-131 nuclides per unit area at the plant site.

[0056] The dynamic migration process of radioactive nuclides in the food chain after deposition includes the suspension, rain splashing, and weathering of radioactive substances in the surface soil and plant surfaces; the penetration, adsorption, and desorption processes in the soil; and the absorption of radioactive substances from the soil and leaf surfaces during plant growth.

[0057] S16. Calculate the food contamination level (Qris1, Qris2, ..., Qris2) caused by radionuclide i in food under the meteorological data conditions according to the ground or leaf deposition concentration Cdris and DS factor. n ).

[0058] According to step S12 and step S15, the pollution level of various foods caused by I-131 nuclides at different distances under the condition of s groups of meteorological data is calculated. The pollution level of milk caused by I-131 nuclides at distance n is:

[0059] QUR I-131 (milk)=Cdrsn I-131 DS I-131 (milk)

[0060] S17. For other nuclides, repeat steps S13 to S16 to calculate the food contamination level (Qrisn) at different distances under the specified meteorological data of each nuclide.

[0061] For Cs-137 and other nuclides, steps S13 to S16 are repeated to obtain the food contamination level QrCs-137 of Cs-137 at each distance under the accident release category r.

[0062] S18. For other meteorological data, repeat steps S13 and S17 to count the food contamination level Qrin of nuclide i at the specified meteorological probability level at n different distances. For each nuclide, sort the activity concentration of nuclide i under various meteorological data conditions from large to small, and count the probability level (DFrin) that the contamination level of nuclide i exceeds the general action level for food at different distances.

[0063] Taking the distance n as an example, in each accident release type, the food contamination levels of I-131 and Cs-137 are Q1n I-131 , Q2n I-131 ,…,Qrn I-131 ;Q1n Cs-137 , Q2n Cs-137 ,…,Qrn Cs-137 ; The probability levels of exceeding the general action level of food are DF1n I-131 ,DF2n I-131 ,…,DFrn I-131 ;DF1n Cs-137 ,DF2n Cs-137 ,…,DFrn Cs-137 .

[0064] S19. For other accident sequences, repeat steps S12-S18, and calculate the weighted value Q = ∑ (fr * Qrin) / ∑ fr of the food contamination level of all nuclides under the specified probability conditions at each distance and the weighted value DF = ∑ (fr * dfrin) / ∑ fr of the meteorological probability level of the food contamination level exceeding the general action level for food at each distance according to the accident occurrence frequency fr. Taking the distance n as an example, the weighted value Qn of the food contamination level of I-131 and Cs-137 and the probability level DFn exceeding the general action level for food are as follows:

[0065]

[0066]

[0067]

[0068]

[0069] S20. Compare the Q value with the general action level of food and give the distance exceeding the general action level. Compare the DF value with the specified probability level limit and give the distance value meeting the specified probability level. In summary, further give the recommended range of the ingestion emergency plan area.

[0070] For I-131, the Q value at each distance is compared with the general action level of 1 kBq / kg for general consumer foods of I-131 and 0.1 kBq / kg for milk, baby food and drinking water to obtain the distance where the contamination level exceeds the limit. And with the 30% probability level as the limit, the distance where the DF value is less than 30% is obtained. For Cs-137, the Q value at each distance is compared with the general action level of 1 kBq / kg for foods to obtain the distance where the contamination level exceeds the limit. And with the 30% probability level as the limit, the distance where the DF value is less than 30% is obtained.

[0071] Based on the distance values ​​of all nuclides, the recommended range of the enveloping ingestion emergency planning area is given.

[0072] S21. Calculate the pollution level of large water bodies within the regional scope based on the recommended values ​​of the ingestion emergency plan area.

[0073] Embodiment 3

[0074] like Figure 3 and Figure 4 As shown, a device for dividing an ingestion emergency plan area for a nuclear power plant disclosed in the present invention includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the method for dividing an ingestion emergency plan area for a nuclear power plant described in Example 1 and Example 2 and its optional implementation methods are implemented.

[0075] The memory is used to store computer-executable instructions, the processor is connected to the memory via the bus, the processor executes the computer-executable instructions stored in the memory, the communication device is responsible for connecting to an external network to perform data transmission and reception; the processor is connected to the memory, and the memory includes database software;

[0076] The database software is a database of SQL Server 2005 or above, and is stored in a computer-readable storage medium; the processor and the memory contain a number of instructions for enabling a personal computer, a server, or a network device to execute all or part of the steps of the method; the processor type used includes a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof; the storage medium includes a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0077] Specifically, the software system is partially carried by a central processing unit (CPU), a general processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logic boxes, modules and circuits described in conjunction with the disclosure of the present invention. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of DSP and microprocessors, and the like. The communication equipment for communication between relevant personnel and users can utilize a transceiver, a transceiver circuit or a communication interface, and the like.

[0078] Those skilled in the art will appreciate that in one or more of the above examples, the functions described in the present invention may be implemented in hardware, software, firmware, or any combination thereof. When implemented using software, the functions may be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any media that facilitates the transmission of a computer program from one place to another. The storage medium may be any available medium that a general or special-purpose computer can access.

[0079] It can be seen from the above embodiments that the method, device and storage medium for dividing the ingestion emergency plan area of ​​a nuclear power plant disclosed in the present invention analyze the diffusion range and occurrence probability of various nuclides, conduct a comprehensive indicator analysis, accurately divide the ingestion emergency plan area, and improve the calculation efficiency.

[0080] It can be directly applied to the design and optimization of the ingestion emergency plan area division in nuclear power plants, laying a technical foundation for the implementation of the third-level probabilistic safety analysis work in nuclear power plants.

[0081] The methods, devices and storage media of the present invention are not limited to the embodiments described in the specific implementation manners. Those skilled in the art may derive other implementation manners based on the technical solutions of the present invention, which also fall within the technical innovation scope of the present invention.

Claims

1. A method for dividing ingestion emergency planning areas in a nuclear power plant, the method comprising the following steps: S1. Consider the hourly meteorological conditions of the plant site in the past year and obtain the corresponding meteorological data group according to the specified meteorological data sampling method; S2. Establish an atmospheric diffusion model for each meteorological data set, and calculate the food contamination level of each nuclide at different distances around the nuclear power plant under each meteorological data set in combination with the release amount of each nuclide in the release category; S3. Combined with the frequency of occurrence of accident sequences, calculate the food contamination level caused by each nuclide after weighting the secondary PSA source term at each distance, calculate the distance at which the food contamination level at each distance exceeds the specified general action level under the specified probability level, and combine with the general action level limit to give the frequency of exceeding the specified general action level limit at each distance; S4. Determine the scope of the ingestion emergency plan area of ​​the nuclear power plant in combination with the frequency limit; Step S2 includes the following sub-steps: S21. For any nuclide i, based on a set of meteorological data s obtained by the sampling method and the atmospheric diffusion model, calculate the near-ground time-integrated air concentration of the radioactive nuclide at different distances from the accident release point; S22, taking into account the dry and wet deposition process of radionuclides, calculating the ground deposition concentration of the radionuclides after taking into account the deposition effect; S23. Considering the dynamic migration process of radioactive nuclides in the food chain after deposition, the preset food chain model is used to calculate the radionuclide activity concentration corresponding to the radioactive deposition per unit area; S24. Calculate the food contamination level caused by radionuclides in the food under the meteorological data conditions based on the ground or leaf surface deposition concentration factor; S25. For other nuclides, repeat steps S21-S24 to calculate the food contamination level of each nuclide at different distances under the meteorological data; S26. For other meteorological data, repeat steps S21-S25 to count the food contamination levels of nuclide i at specified meteorological probability levels at n different distances; Step S3 includes the following sub-steps: S31. For each nuclide, rank the activity concentration of the nuclide under various meteorological data conditions from large to small, and calculate the probability level of the nuclide contamination level exceeding the general action level for food at different distances; S32. For other accident sequences, repeat steps S21-S26 to count the food contamination level of nuclide i under each accident release type at n different distances and at the specified meteorological probability level; S33. Calculate the weighted values ​​of the food contamination levels of each nuclide at the specified meteorological probability level at different distances, taking into account the frequency of accidents; Calculate the weighted values ​​of the meteorological probability level of the food contamination levels of each nuclide at different distances exceeding the general action level for food, taking into account the frequency of accidents; Step S4 includes comparing the weighted value of the food contamination level of each nuclide at the specified meteorological probability level at different distances with the general action level for food to obtain the distance exceeding the general action level; comparing the weighted value exceeding the general action level for food with the specified probability level limit to obtain the distance value that meets the specified probability level, and further determining the scope of the ingestion emergency plan area.

2. A method for dividing nuclear power plant ingestion emergency plan areas according to claim 1, characterized in that: Step S1 includes setting the number of release categories of the secondary PSA source term, and setting the stockpile and release share of each nuclide for any of the secondary PSA accident sequences.

3. A method for dividing nuclear power plant ingestion emergency plan areas according to claim 1, characterized in that: The meteorological data sampling method specified in step S1 includes random sampling or stratified sampling.

4. A method for dividing nuclear power plant ingestion emergency plan areas according to claim 1, characterized in that: The preset food chain model in step S23 is a semi-dynamic food chain model.

5. A method for dividing nuclear power plant ingestion emergency plan areas according to claim 1, characterized in that: The method further comprises the step of calculating the pollution level of large water bodies within the regional range according to the scope of the ingestion emergency plan area.

6. A device for dividing the ingestion emergency plan area of ​​a nuclear power plant, characterized by: The invention comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements a method for dividing an ingestion emergency plan area of ​​a nuclear power plant as claimed in any one of claims 1 to 5 when executing the computer program.

7. A storage medium having a computer program stored thereon, characterized in that: The computer program is configured to implement a method for dividing ingestion emergency plan areas for a nuclear power plant as described in any one of claims 1 to 5 when executed.

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