Method and device for determining maximum 2-hour source item and method and system for determining maximum 2-hour accident source item under design extension working condition

Abstract

The invention discloses a maximum 2-hour source item determination method and device, and a maximum 2-hour accident source item determination method and system under a design extension working condition, and relates to the technical field of nuclear industry. The maximum 2-hour source item determination method comprises the following steps: acquiring M * K cumulative release shares; for each cumulative release share in the M * K cumulative release shares, determining an environmental release source item corresponding to the cumulative release share; for each environment release source item in the M * K environment release source items, determining a first effective dose corresponding to the environment release source item; and determining a maximum 2-hour source item of the first accident according to the M * K first effective doses. According to the embodiment of the invention, the method can improve the determination accuracy of the maximum 2-hour source item of the first accident, and can provide possibility for the subsequent improvement of the determination accuracy of the maximum 2-hour accident source item under the design extension working condition of a nuclear power plant.

Description

Technical Field

[0001] The present application belongs to the field of nuclear industry technology, and specifically relates to a method and device for determining a maximum 2-hour source term, and a method and system for determining a maximum 2-hour accident source term under design expansion conditions. Background Art

[0002] According to the Regulations on Environmental Radiation Protection of Nuclear Power Plants (GB 6249-2011), the site selection stage of a nuclear power plant requires the evaluation of the consequences of hypothetical accidents in the site selection to determine the scope of non-residential areas and planned restricted areas. Among them, since the boundary of the non-residential area is close to the center of the reactor and the accident source items to be considered are large, its radioactive consequences are of greater concern in engineering practice. For non-residential areas, it should be ensured that the effective dose received by any individual on its boundary through immersion external exposure and inhalation internal exposure within any 2 hours after the accident does not exceed 0.25Sv. For any 2 hours, in engineering practice, the corresponding consequences of the source items for each 2 hours are analyzed, and the maximum consequence is used to determine whether the 2-hour dose meets the above limit.

[0003] For traditional large light water reactor nuclear power plants, the early U.S. federal regulations "Reactor Siting Criteria (10CFR100)" and the NRC's recent regulatory guidelines "Radioactive Source Terms for Evaluating Design Basis Accidents in Nuclear Power Plants (RG1.183)" have already identified hypothetical accident source terms for them, but for small nuclear power plants, there is still a lack of corresponding regulations or standards at home and abroad.

[0004] According to the "Principles for Safety Review of Small Pressurized Water Reactor Nuclear Power Plants (Trial)", in view of the design concept of small pressurized water reactor nuclear power plants and to adapt to their higher safety goals, it is required to analyze the important event sequences of design basis accidents and beyond design basis accidents of small pressurized water reactor nuclear power plants to determine the release of radioactive materials, and select conservative and enveloping source items as source items for site selection and emergency planning to evaluate whether the safety goals are met.

[0005] As an important input for dose assessment, the maximum 2-hour source term of the hypothetical accident in the site selection is an important determinant of the accident consequences, which in turn affects the determination of the boundary range of the non-residential area. In order to reflect the progress of advanced reactor design, the possibility of selecting hypothetical accident source terms different from RG1.183 is explored to recommend hypothetical accident source terms for the site selection that are suitable for the safety level of the reactor type.

[0006] In 2016, the National Nuclear Safety Administration issued a new version of the "Nuclear Power Plant Design Safety Regulations" (HAF102-2016), which put forward clear requirements for the prevention and mitigation of severe accidents, and required source term and consequence analysis for the design extended condition of core melting (hereinafter referred to as DEC-B). In the prior art, the maximum 2-hour accident source term under the design extended condition of a nuclear power plant is generally determined by a source term calculation model. The source term calculation model is usually based on some assumptions, such as steady-state release and uniform release. In actual emergency situations, these assumptions may not be fully established, thereby affecting the accuracy of determining the maximum 2-hour accident source term under the design extended condition of a nuclear power plant. Summary of the invention

[0007] The technical problem to be solved by the present application is to provide a method and device for determining a maximum 2-hour source term in view of the above-mentioned deficiencies in the prior art, and to design a method and system for determining a maximum 2-hour accident source term under extended operating conditions. This method can be used to determine the maximum 2-hour source term of the first accident, thereby providing a possibility for subsequent determination of the maximum 2-hour accident source term under extended operating conditions of a nuclear power plant design.

[0008] In a first aspect, an embodiment of the present application provides a method for determining a maximum 2-hour source term, which is applied to a first accident in a nuclear power plant, the method comprising: for each nuclide grouping in the K groups of nuclide groupings under the first accident, obtaining M cumulative release shares of the nuclide grouping that correspond one to one within 2 hours from the start time of M targets, to obtain M×K cumulative release shares, where M and K are both positive integers; for each of the M×K cumulative release shares, determining the environmental release source term corresponding to the cumulative release share, to obtain M×K environmental release source terms; for each of the M×K environmental release source terms, determining the first effective dose corresponding to the environmental release source term, to obtain M×K first effective doses; and determining the maximum 2-hour source term for the first accident based on the M×K first effective doses.

[0009] Based on the same inventive concept, in the second aspect, an embodiment of the present application also provides a method for determining a maximum 2-hour accident source term under a design expansion condition, which is applied to a nuclear power plant, and the method comprises: determining a plurality of maximum 2-hour source terms for first accidents according to the method for determining a maximum 2-hour source term for an accident in any one of the first aspects, and determining a first effective dose corresponding to a maximum 2-hour source term for each first accident among the plurality of maximum 2-hour source terms for first accidents as a second effective dose; and determining the maximum 2-hour source term for the first accident corresponding to the second effective dose with the largest numerical value as the maximum 2-hour accident source term under the design expansion condition.

[0010] Based on the same inventive concept, in a third aspect, a maximum 2-hour source term determination device is applied to a nuclear power plant, and the device includes: a first acquisition module, for obtaining, for each nuclide group in the K groups of nuclide groups under the first accident, M corresponding cumulative release shares of the nuclide group within 2 hours from the start time of M targets, so as to obtain M×K cumulative release shares, where M and K are both positive integers; a first determination module, connected to the first acquisition module, for determining, for each cumulative release share in the M×K cumulative release shares, the environmental release source term corresponding to the cumulative release share, so as to obtain M×K environmental release source terms; a second determination module, connected to the first determination module, for determining, for each environmental release source term in the M×K environmental release source terms, the first effective dose corresponding to the environmental release source term, so as to obtain M×K first effective doses; a third determination module, connected to the second determination module, for determining the maximum 2-hour source term of the first accident based on the M×K first effective doses.

[0011] Based on the same inventive concept, in the fourth aspect, an embodiment of the present application also provides a system for determining a maximum 2-hour accident source term under a design extension condition, which is applied to a nuclear power plant, and the system includes: a device for determining a maximum 2-hour accident source term under a design extension condition, and a device for determining a maximum 2-hour source term as in any one of the third aspects; wherein the device for determining a maximum 2-hour source term is used to determine a plurality of maximum 2-hour source terms for first accidents, and to determine a first effective dose corresponding to a maximum 2-hour source term for each first accident among the plurality of maximum 2-hour source terms for first accidents as a second effective dose; the device for determining a maximum 2-hour accident source term under a design extension condition includes: a fourth determination module, connected to the device for determining a maximum 2-hour source term for a first accident corresponding to a second effective dose having the largest numerical value, as the maximum 2-hour accident source term under the design extension condition.

[0012] According to the method and device for determining the maximum 2-hour source term provided in the embodiment of the present application, a method and system for determining the maximum 2-hour accident source term under extended operating conditions are designed. By considering the M×K cumulative release shares corresponding to the K groups of nuclides, the cumulative release shares can be obtained more comprehensively; by gradually converting the cumulative release shares into environmental release source terms and the first effective dose, the maximum 2-hour source term of the first accident is finally determined according to the first effective dose, which reduces the reliance on the uniform release assumption and the simplified model, and can improve the accuracy of determining the maximum 2-hour source term for the first accident, thereby providing a possibility for subsequently improving the accuracy of determining the maximum 2-hour accident source term under the extended operating conditions of the nuclear power plant design. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic flow chart of a method for determining a maximum 2-hour source term provided in an embodiment of the present application is shown;

[0014] Figure 2 A schematic diagram showing various first change curves provided in an embodiment of the present application;

[0015] Figure 3 A schematic diagram showing various total release fraction curves provided in the embodiments of the present application;

[0016] Figure 4 A schematic diagram showing various cumulative release shares provided in the embodiments of the present application;

[0017] Figure 5 A schematic diagram showing various first effective doses provided in the embodiments of the present application;

[0018] Figure 6 A flow chart showing a method for determining a maximum 2-hour accident source item under a design expansion condition provided in an embodiment of the present application;

[0019] Figure 7 Another flow chart of a method for determining a maximum 2-hour accident source item under a design expansion condition provided in an embodiment of the present application is shown;

[0020] Figure 8 A schematic diagram showing a structure of a device for determining a maximum 2-hour source term provided in an embodiment of the present application is shown;

[0021] Fig. 9 A structural schematic diagram of a system for determining a maximum 2-hour accident source item under a design expansion condition provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0023] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0024] 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.

[0025] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] To facilitate understanding of the maximum 2-hour source term determination method provided in the embodiment of the present application, the prior art that may be involved in the embodiment of the present application is described below.

[0027] In 2016, the National Nuclear Safety Administration issued a new version of the "Nuclear Power Plant Design Safety Regulations" (HAF102-2016), which put forward clear requirements for the prevention and mitigation of severe accidents, and required source term and consequence analysis for the design extension condition of core melting (hereinafter referred to as DEC-B). The inventors found that the DEC-B accident took into account the core melting, and the accident process took into account the design of the reactor type severe accident mitigation measures. In the current safety analysis, the selection of the DEC-B accident sequence takes into account the selection principle based on engineering judgment, determinism, and probability evaluation. The analyzed accident sequence is representative, and the integrated severe accident analysis program MAAP5 is used for the DEC-B accident source term. The source term calculation process is closely combined with the design characteristics of the model and the accident process. The source term calculation results are more in line with reality, and conservative and enveloping source terms can be selected as the source terms for site selection and emergency planning.

[0028] The inventors have found that the design of extended operating condition source terms usually uses the severe accident integrated program MAAP4, MAAP5 or MELCOR program to calculate the relative mass share of each group of substances released from the core to the environment. In order to analyze the consequences, it is necessary to deduce the environmental release source term based on the mass share and core parameters. For the maximum 2-hour source term, it is necessary to intercept the accident release share every 2 hours, and calculate the dose consequences every 2 hours based on the nuclide type corresponding to each group of release shares, combined with parameters such as core inventory, dose conversion factor, and atmospheric dispersion factor, and select the source term with the most serious consequences as the maximum 2-hour source term.

[0029] Example 1

[0030] Figure 1 A flow chart of a method for determining a maximum 2-hour source term provided in an embodiment of the present application is shown.

[0031] The maximum 2-hour source term determination method provided in the embodiment of the present application can be applied to the first accident of a nuclear power plant. A nuclear power plant may include a small nuclear power plant. Among them, the International Atomic Energy Agency (IAEA) defines a small nuclear power plant as a nuclear power plant below 300MWe. The first accident can be any accident of a nuclear power plant.

[0032] The maximum 2-hour source term determination method provided in the embodiment of the present application can be executed by an electronic device and a maximum 2-hour source term determination device, etc. The following description is given by assuming that the maximum 2-hour source term determination method is executed by an electronic device.

[0033] like Figure 1 As shown, the maximum 2-hour source term determination method provided in the embodiment of the present application may include steps S110 to S140.

[0034] S110. For each nuclide group in the K nuclide groups under the first accident, obtain M cumulative release shares of the nuclide group within 2 hours from the start time of the M targets, so as to obtain M×K cumulative release shares, where M and K are both positive integers.

[0035] S120 . For each cumulative release share among the M×K cumulative release shares, determine an environment release source item corresponding to the cumulative release share to obtain M×K environment release source items.

[0036] S130. For each of the M×K environmental release source items, determine a first effective dose corresponding to the environmental release source item to obtain M×K first effective doses.

[0037] S140. Determine the maximum 2-hour source term of the first accident based on M×K first effective doses.

[0038] According to the maximum 2-hour source term determination method provided by the embodiments of the present application, by considering the M×K cumulative release fractions corresponding to K groups of nuclide groupings, the cumulative release fractions can be obtained more comprehensively; by gradually converting the cumulative release fractions into environmental release source terms and the first effective dose, and finally determining the maximum 2-hour source term of the first accident according to the first effective dose, the dependence on the uniform release assumption and the simplified model is reduced, the accuracy of determining the maximum 2-hour source term of the first accident can be improved, and thus it is possible to provide a possibility for improving the accuracy of determining the maximum 2-hour accident source term under the design extended conditions of nuclear power plants in the future.

[0039] The following introduces the specific implementation manners of the above steps.

[0040] In step S110, each nuclide grouping in the K groups of nuclide groupings may include P nuclides. It should be noted that for different nuclide groupings, the value of P may be different. For example, the first group of nuclide groupings in the K groups of nuclide groupings may include 2 nuclides, that is, the value of P is 2; the fourth group of nuclide groupings in the K groups of nuclide groupings may include 3 nuclides, that is, the value of P is 3.

[0041] Exemplarily, the value of M may be 2, 3, 10, 15, etc.

[0042] It should be noted that the values of P and M in the embodiments of the present application can be set according to actual situations, and the two may be equal or not equal, which is not limited herein.

[0043] Exemplarily, the K groups of nuclide groupings under the first accident may be pre-stored in the electronic device for subsequent direct call.

[0044] Taking the value of K as 9 as an example, Table 1 exemplarily shows the names of 9 groups of nuclide groupings and the included nuclides.

[0045] Table 1

[0046]

[0047]

[0048] It should be noted that the number of nuclide groupings, names, and included nuclides in Table 1 are only for examples and are not used to limit the present application. The number of nuclide groupings, names, and included nuclides can be set according to actual situations.

[0049] The target start time may be the start time of the 2-hour source term.

[0050] In some examples, the first target start time among the M target start times is the start release time of the first accident, and the difference between the mth target start time and the (m + 1)th target start time is 0.01 hours, 0 ≤ m < M, and m is an integer.

[0051] That is to say, starting from the release time t0 of the first accident, every 0.01 hour is used as an interval, and until 2 hours before the end release time (i.e., the end time) is taken as the target start time T0, that is, the target start time T0 corresponding to the entire duration T of the first accident can satisfy: T0 = (t0, t0+0.01, t0+0.02, ... t e -2), the unit of the target start time T0 is h. The end time Te = T0 + 2, the unit of the end time Te is h.

[0052] In some embodiments, before obtaining the M cumulative release shares of the nuclide groups corresponding to each other within 2 hours from the start time of the M targets, the method further includes:

[0053] Obtain K target parameter groups corresponding to K groups of nuclides under the first accident;

[0054] Obtain the M cumulative release shares of the nuclide groups corresponding to each other within 2 hours from the start time of the M targets, including:

[0055] According to the target parameter groups corresponding to the nuclide groups, M corresponding cumulative release shares of the nuclide groups within 2 hours from the start time of the M targets are determined.

[0056] Exemplarily, each of the K target parameter groups includes a first release share group and a first initial mass group. The first release share group includes J first change curves corresponding to J types of radioactive materials, the first initial mass group includes J initial masses corresponding to J types of radioactive materials, and the first change curve is a curve of the change of the release share of radioactive materials to the environment relative to the initial mass of the core over time during the first accident.

[0057] Exemplarily, there are Q types of radioactive materials under the first accident, Q is greater than or equal to J and Q is a positive integer. The electronic device stores a first change curve corresponding to each of the Q types of radioactive materials, that is, Q first change curves, and an initial core mass corresponding to each of the Q types of radioactive materials, that is, Q core initial masses. Based on the entire duration of the first accident, Q first release share groups and Q first initial mass groups can be determined according to the Q first change curves and the Q core initial masses. Among them, the value of Q can be set according to the actual situation and is not limited here.

[0058] Exemplarily, the value of Q can be 18, and the Q radioactive substances can be noble gas, cesium iodide CsI, tellurium dioxide TeO2, strontium oxide SrO, molybdenum dioxide MoO2, cesium hydroxide CsOH, barium oxide BaO, lanthanum oxide La2O3, cerium oxide CeO2, antimony Sb, antimony Te2, uranium dioxide UO2, silver Ag, iodine I2, iodomethane CH3I, cesium molybdenum oxide Cs2MoO4, ruthenium Ru and plutonium Pu. That is to say, noble gas is the first radioactive substance, cesium iodide CsI is the second radioactive substance, tellurium dioxide TeO2 is the third radioactive substance, strontium oxide SrO is the fourth radioactive substance, and so on. Q initial core mass m t Can satisfy: m t =[m1, m2, m3, m4, m5, m6, m7, m8, m9, m 10 , m 11 , m 12 , m 13 , m 14 , m 15 , m 16 , m 17 , m 18 ], for example, m t =[521.6, 33.96, 53.12, 102.58, 463.65, 120.57, 147.30, 1248.87, 367.01, 1.38, 42.5, 93794.5, 4848.6, 0.87, 0.03, 271.97, 284.44, 912.78]. Initial core mass m t The unit is kg. The first Q change curve can be Figure 2 As shown. Among them, Figure 2 The horizontal axis of each first change curve is time, the unit of time is h, and the vertical axis is the release ratio, the unit is 100%. It should be noted that the above numerical values ​​and the first change curve are only used for examples and are not used to limit the present application.

[0059] For the sake of convenience, in the embodiment of the present application, the first change curve corresponding to the noble gas is recorded as f1, the first change curve corresponding to the cesium iodide CsI is recorded as f2, the first change curve corresponding to the tellurium dioxide TeO2 is recorded as f3, the first change curve corresponding to the strontium oxide SrO is recorded as f4, and so on, until the first change curve corresponding to the plutonium Pu is recorded as f 18 .

[0060] It should be noted that for different nuclide groups, the value of J in the J types of radioactive materials to which the P types of nuclides belong respectively may be different. For example, the J types of radioactive materials to which the P types of nuclides belong respectively in the first group of nuclides in the K group of nuclides may be 1 type of radioactive material, that is, the value of P is 1; the J types of radioactive materials to which the P types of nuclides belong respectively in the fourth group of nuclides in the K group of nuclides may be 3 types of radioactive materials, that is, the value of P is 3. And P and J may be equal or different, which is not limited here.

[0061] In some embodiments, the target parameter group includes a first release fraction group and a first initial mass group.

[0062] Obtain K target parameter groups corresponding to K groups of nuclides under the first accident, including:

[0063] Get the second release share group and the second initial quality group, where both the second release share group and the second initial quality group are empty arrays;

[0064] For each nuclide group in the K groups of nuclides under the first accident, determine the J types of radioactive materials to which the P types of nuclides in the nuclide group belong respectively, so as to obtain K×J types of radioactive materials;

[0065] For each nuclide group in the K nuclide groups under the first accident, J first change curves corresponding to J types of radioactive materials are stored in the second release share group to obtain the first release share group, so as to obtain K first release share groups;

[0066] For each nuclide group in the K nuclide groups under the first accident, J initial masses of J types of radioactive materials are stored one by one into the second initial mass group to obtain the first initial mass group, so as to obtain K first initial mass groups.

[0067] Exemplarily, the second release share group and the first initial mass group are both empty arrays, that is, the second release share group T t =[], the second initial mass group M=[].

[0068] As an example, inert gases include xenon Xe and krypton Kr. The radioactive materials to which xenon Xe and krypton Kr belong respectively are inert gases, which are radioactive materials. Therefore, the first release share group corresponding to the inert gas is T1=[f1], and the corresponding first initial mass group is M1=[m1].

[0069] As another example, halogens include iodine I and bromine Br. The radioactive substances to which iodine I belongs include three radioactive substances: cesium iodide CsI, iodine I2, and methyl iodide CH3I. The radioactive substances to which bromine Br belongs do not exist. Therefore, the first release share group corresponding to halogens is T2=[f2, f 14 , f15 ], and its corresponding first initial mass group is M2=[m2,m 14 , m 15 ].

[0070] As another example, alkali metals include cesium Cs and rubidium Rb. The radioactive substances to which cesium Cs belongs include three radioactive substances: cesium iodide CsI, cesium hydroxide CsOH, and cesium molybdenum oxide Cs2MoO4. The radioactive substances to which rubidium Rb belongs do not exist. Therefore, the first release share group corresponding to the alkali metal is T3=[f2, f6, f 16 ], and its corresponding first initial mass group is M3 = [m2, m6, m 16 ].

[0071] As another example, the tellurium group includes tellurium Te, antimony Sb and selenium Se. The radioactive substances to which tellurium Te belongs include two radioactive substances, tellurium dioxide TeO2 and antimony Te2. The radioactive substances to which antimony Sb belongs include antimony Sb, a radioactive substance. The radioactive substance to which selenium Se belongs does not exist. Therefore, the first release share group corresponding to the tellurium group is T4=[f3, f 10 , f 11 ], and its corresponding first initial mass group is M4=[m3,m 10 , m 11 ].

[0072] In the present embodiment, the 9 nuclides shown in Table 1 are grouped, and Figure 2 The 18 first variation curves shown, m t =[m1,m2,m3,m4,m5,m6,m7,m8,m9,m 10 , m 11 , m 12 , m 13 , m 14 , m 15 , m 16 , m 17 , m 18 ] as an example, the K first released share groups obtained are T1 = [f1], T2 = [f2, f 14 , f 15 ]、T3=[f2,f6,f 16 ]、T4=[f3,f 10 , f 11 ], T5 = [f4], T6 = [f5, f 16 , f 17 ], T7 = [f8], T8 = [f9, f 12 , f 18 ] and T9 = [f7], the obtained K first initial mass groups are M1 = [m1], M2 = [m2, m14 , m 15 ]、M3=[m2,m6,m 16 ]、M4=[m3,m 10 , m 11 ], M5 = [m4], M6 = [m5, m 16 , m 17 ], M7=[m8], M8=[m9,m 12 , m 18 ] and M9=[m7].

[0073] It should be noted that some radioactive substances may include at least two nuclides. For example, CsI includes two nuclides, Cs and I. These two nuclides belong to the two nuclide groups of halogen (I) and alkali metal elements (Cs). Therefore, the release share of CsI needs to be considered in both nuclide groups.

[0074] In some embodiments, according to the target parameter group corresponding to the nuclide group, determining M cumulative release shares of the nuclide group corresponding to each other within 2 hours from the M target start time includes:

[0075] Determine the total release share curve of the nuclide group during the first accident duration according to the target parameter group corresponding to the nuclide group;

[0076] According to the total release share curve, determine the M corresponding cumulative release shares of the nuclide groups within 2 hours from the starting time of the M targets.

[0077] For example, the total release fraction curve may be a curve showing the change of the release fraction of the nuclide grouping over time.

[0078] In some examples, the target parameter group includes a first release share group and a first initial mass group, the first release share group includes J first change curves corresponding to J types of radioactive materials one by one, the first initial mass group includes J initial masses corresponding to J types of radioactive materials one by one, and the first change curve is a curve of change over time of the release share of radioactive materials to the environment relative to the initial mass of the core during the duration of the first accident;

[0079] According to the target parameter group corresponding to the nuclide group, the total release share curve of the nuclide group during the first accident duration is determined, including:

[0080] Substitute the J first change curves and the J initial masses into formula (1) to calculate and obtain the total release share curve of the nuclide group during the first accident duration;

[0081] Formula (1) includes:

[0082]

[0083] Among them, F k represents the total release share curve of the kth nuclide group during the first accident duration; T kj represents the jth first variation curve corresponding to the kth nuclide group; M kj Indicates the jth initial mass corresponding to the kth nuclide group; j≤J, k≤K.

[0084] For example, the 9 total release fraction curves determined in the examples of the present application are as follows: Figure 3 shown. Figure 3 The horizontal axis is time, the unit of time is h, and the vertical axis is the release share, the unit is 100%.

[0085] In some examples, according to the total release share curve, determining M cumulative release shares of the nuclide grouping corresponding to each other within 2 hours from the start time of the M targets includes:

[0086] For each of the M target start times, substitute it and its corresponding target end time into formula (1) to obtain the first release share corresponding to the target start time and the second release share corresponding to the target end time, so as to obtain M first release shares and M second release shares. The target end time is a time 2 hours later than its corresponding target start time.

[0087] For each of the M target start times, the difference between the corresponding second release share and the first release share is determined as the cumulative release share, so as to obtain M corresponding cumulative release shares of the nuclide grouping within 2 hours from the M target start times.

[0088] Exemplarily, the target end time is the end time corresponding to the target start time. For example, if the target start time is t0, then its corresponding target end time is t0+2, in units of h.

[0089] For example, the M cumulative release shares corresponding to each nuclide group in the embodiment of the present application are as follows: Figure 4 shown. Figure 4 The horizontal axis represents time, with the unit being h; the vertical axis represents the cumulative release share every 2 hours, that is, the cumulative release share that corresponds one by one within 2 hours from the target start time, with the unit being 100%.

[0090] In step S120, after obtaining the M corresponding cumulative release shares of the nuclide groups within 2 hours from the starting time of the M targets to obtain M×K cumulative release shares, the electronic device can also determine the environmental release source item corresponding to the cumulative release share for each of the M×K cumulative release shares to obtain M×K environmental release source items.

[0091] In some examples, the environmental release source term includes the activities of N nuclides, where N is a positive integer;

[0092] Determine the environmental release source items corresponding to the cumulative release share, including:

[0093] Obtain the release start time of the first accident, the N nuclides corresponding to the cumulative release share, and the N nuclide parameter groups corresponding to the N nuclides one by one, the nuclide parameter groups including the nuclide stock, the ratio of different chemical forms of nuclides and the nuclide decay coefficient;

[0094] For each of the N nuclides, the release start time, cumulative release fraction and the nuclide parameter group corresponding to the nuclide are substituted into formula (2) to calculate the activity of the nuclide, so as to obtain the activity of the N nuclides;

[0095] Formula (2) includes:

[0096]

[0097] Where T0 represents the target starting time; n represents the nth nuclide; It represents the activity of the nth nuclide released from the target starting time T0; S n Indicates the nuclide stock of the nth nuclide; It represents the cumulative release share of the nth nuclide within 2 hours from the target starting time T0; represents the nuclide decay coefficient of the nth nuclide from the start of the first accident to the target start time T0; C n It represents the ratio of different chemical forms of the nth nuclide.

[0098] Exemplarily, the start release time of the first accident may be stored in the electronic device for subsequent direct use.

[0099] Exemplarily, the electronic device may store mapping relationships between multiple preset cumulative release shares and multiple preset nuclides, as well as mapping relationships between each nuclide and its corresponding nuclide group parameter, so that the N nuclides corresponding to the cumulative release shares may be obtained first, and then the N nuclides parameter groups corresponding to the N nuclides may be determined based on the N nuclides. More specifically, the electronic device may pre-store mapping relationships between nuclides and nuclide accumulations, mapping relationships between nuclides and ratios of different chemical forms of nuclides, and mapping relationships between nuclides and nuclide decay coefficients.

[0100] It should be noted that the value of N can be set according to actual conditions, and the values ​​of N and P can be equal or unequal, which is not limited here.

[0101] For example, the mapping relationship between nuclides and nuclide accumulation can be shown in Table 2.

[0102] Table 2

[0103]

[0104]

[0105] It should be noted that the above numerical values ​​are only used for examples and are not intended to limit the present application.

[0106] Taking nuclide I-131 as an example, the nuclide stock S I-131 =3.21e+18Bq, target start time T0 = 0.41h, cumulative release share F 0.41-2.41 =2.82e-05 (unit 100%), the nuclide decay coefficient of I-131 is 3.59e-03h -1 According to the initial core mass, different iodine forms are divided, with aerosol iodine (aer) accounting for 97.42%, elemental iodine (ele) accounting for 2.49%, and organic iodine (org) accounting for 0.09%.

[0107] Q 0.41-2.41 (I-131(aer))=S I-131 ×F 0.41-2.41 (I-131)×exp(-λ I-131 ×T0)×C aer

[0108] =3.21e+18×2.82e-05×exp(-3.59e-03×0.41)×0.9742=7.55e+13Bq

[0109] Q 0.41-2.41 (I-131(ele))=3.21e+18×2.82e-05×exp(-3.59e-03×0.41)×0.0249

[0110] =8.38e+12Bq

[0111] Q 0.41-2.41 (I-131(org))=3.21e+18×2.82e-05×exp(-3.59e-03×0.41)×0.0009

[0112] =2.89e+11Bq

[0113] In step S130, after the electronic device determines the environmental release source item corresponding to the cumulative release share for each of the M×K cumulative release shares to obtain M×K environmental release source items, it can also determine the first effective dose corresponding to the environmental release source item for each of the M×K environmental release source items to obtain M×K first effective doses.

[0114] In some examples, the environmental release source term includes the activities of N nuclides;

[0115] Determine the first effective dose corresponding to the environmental release source term, including:

[0116] Obtain the maximum value of the atmospheric diffusion factor, the respiration rate, and N conversion factors corresponding to the activities of N types of nuclides, including the conversion factor of air immersion external radiation dose and the conversion factor of inhalation internal radiation dose;

[0117] Substitute the N air immersion external radiation dose conversion factors corresponding to the maximum value of the atmospheric diffusion factor and the activity of the N nuclides into formula (3) to calculate the air immersion external radiation dose;

[0118] Formula (3) includes:

[0119]

[0120] in, It represents the air immersion external exposure corresponding to the environmental release source term released from the target starting time T0; Indicates the activity of the nth nuclide released from the target starting time T0; Indicates the maximum atmospheric diffusion factor; DFA n It represents the air immersion external radiation dose conversion factor corresponding to the activity of the nth nuclide;

[0121] Substitute the N inhalation internal radiation dose conversion factors corresponding to the maximum value of the atmospheric diffusion factor, the respiration rate, and the activity of the N nuclides into formula (4) to calculate the inhalation internal radiation dose;

[0122] Formula (4) includes:

[0123]

[0124] in, represents the inhaled internal exposure corresponding to the environmental release source term released at the target starting time T0; BR represents the breathing rate; DFI n The conversion factor of inhalation internal radiation dose corresponding to the activity of the nth nuclide;

[0125] Substitute the air immersion external exposure and the inhalation internal exposure into formula (5) to calculate the first effective dose corresponding to the environmental release source term;

[0126] Formula (5) includes:

[0127]

[0128] in, Represents the first effective dose corresponding to the environmental release source term.

[0129] Exemplarily, the electronic device may pre-store N conversion factors corresponding to the maximum value of the atmospheric diffusion factor, the breathing rate, and the activities of N types of nuclides, so as to be directly called later.

[0130] Taking radionuclide I-131 (aer) as an example, the dose conversion factor for external irradiation under air immersion is

[0131] DFA=1.85e-14(Sv·m 3 ) / (Bq·s) and inhalation internal radiation dose conversion factor DFI=7.40e-09Sv / Bq, atmospheric diffusion factor X / Q=1.25e-04s / m 3 , breathing rate BR = 3.5 × 10 -4 m 3 / s, calculated according to formula (3):

[0132] Air immersion external exposure:

[0133] DA 0.41-2.41 (I-131(aer))=7.55e+13×1.25e-04×1.85e-14=1.74e-04Sv

[0134] Inhalation internal exposure:

[0135] DI 0.41-2.41 (I-131(aer))=7.55e+13×1.25e-04×3.5e-4×7.40e-09=2.44e-02Sv

[0136] According to formula (5), the first effective dose corresponding to each nuclide in the environmental release source term is calculated in turn to obtain the first effective dose corresponding to the environmental release source term.

[0137] For example, the M×K first effective doses determined in the embodiment of the present application can be as follows: Figure 5 As shown. Among them, Figure 5 The horizontal axis can represent the initial release time corresponding to the 2-hour source term, that is, the target starting time corresponding to the 2-hour source term, in h; the vertical axis can represent the effective dose, in Sv; the total effective dose is the first effective dose; the plume immersion external exposure dose is the air immersion external exposure dose.

[0138] In step S140, after the electronic device determines the first effective dose corresponding to each of the M×K environmental release source items to obtain M×K first effective doses, it can also determine the maximum 2-hour source item of the first accident based on the M×K first effective doses.

[0139] In some examples, determining a maximum 2-hour source term for a first accident based on the M×K first effective doses includes:

[0140] The environmental release source item corresponding to the first effective dose with the largest value among the M×K first effective doses is determined as the maximum 2-hour source item of the first accident.

[0141] For example, the M×K first effective doses determined in the embodiment of the present application are as follows: Figure 5 Taking the example shown in the figure, the environmental release source item corresponding to 98.52mSv is determined as the maximum 2-hour source item for the first accident.

[0142] Exemplarily, the maximum 2-hour source item of the first accident determined in the embodiment of the present application may be as shown in Table 3.

[0143] Table 3

[0144]

[0145]

[0146] DEC-B LOCA may represent the design extended condition of the first accident, and 0.41-2.41h indicates that the target start time is 0.41h and the target end time is 2.41h.

[0147] In some examples, before determining the environmental release source term corresponding to the first effective dose with the largest value among the M×K first effective doses as the maximum 2-hour source term for the first accident, the method further includes:

[0148] Sort the M×K first effective doses according to their numerical values ​​to obtain a first effective dose sequence;

[0149] A first effective dose having the largest value among M×K first effective doses is determined from the first effective dose sequence.

[0150] In this way, after obtaining the first effective dose sequence, the first effective dose with the largest value among the M×K first effective doses can be intuitively determined.

[0151] Based on the same inventive concept, an embodiment of the present application also provides a method for determining a maximum 2-hour accident source term under a design expansion condition. The method for determining a maximum 2-hour accident source term under a design expansion condition is described below.

[0152] Example 2

[0153] Figure 6 A flow chart showing a method for determining a maximum 2-hour accident source item under a design expansion condition provided in an embodiment of the present application is shown.

[0154] The method for determining the maximum 2-hour accident source term under the design expansion condition provided in the embodiment of the present application can be applied to nuclear power plants.

[0155] The method for determining the maximum 2-hour accident source item under the design extension condition provided in the embodiment of the present application can be executed by an electronic device and a system for determining the maximum 2-hour accident source item under the design extension condition. The following is an explanation of the method for determining the maximum 2-hour accident source item under the design extension condition executed by an electronic device.

[0156] like Figure 6 As shown, the method for determining the maximum 2-hour accident source item under the design extension condition provided in the embodiment of the present application may include steps S610 to S620.

[0157] S610. According to the method for determining the maximum 2-hour source term of an accident in any one of Embodiment 1, determine the maximum 2-hour source terms of multiple first accidents, and determine the first effective dose corresponding to the maximum 2-hour source term of each first accident among the maximum 2-hour source terms of the multiple first accidents as the second effective dose.

[0158] The specific implementation of step S610 can refer to the relevant description of embodiment 1, which will not be repeated here.

[0159] In step S610, the second effective dose is the first effective dose corresponding to the maximum 2-hour source item of each first accident.

[0160] S620. Determine the maximum 2-hour source term of the first accident corresponding to the second effective dose with the largest value as the maximum 2-hour accident source term under the design expansion condition.

[0161] Exemplarily, the second effective dose of the first accident A is Da_max2h=98.52mSv=9.85e-02Sv, the second effective dose of the first accident B is Db_max2h=4.72e-02Sv, and the second effective dose of the first accident C is Dc_max2h=1.54e-02Sv. Since Da_max2h is the largest, the maximum 2-hour source item of the first accident A corresponding to Da_max2h is used as the maximum 2-hour accident source item under the design expansion condition, that is, as the maximum 2-hour accident source item S_max2h for the hypothetical accident of this reactor type site selection.

[0162] According to the method for determining the maximum 2-hour accident source term under the design extension condition provided in the embodiment of the present application, the maximum 2-hour source term for multiple first accidents is determined by the method for determining the maximum 2-hour source term for an accident in any one of the embodiments, and the first effective dose corresponding to the maximum 2-hour source term for each first accident in the maximum 2-hour source terms of the multiple first accidents is determined as the second effective dose; then the maximum 2-hour source term for the first accident corresponding to the second effective dose with the largest value can be determined as the maximum 2-hour accident source term under the design extension condition. In this way, the embodiment of the present application can accurately and reasonably determine the maximum 2-hour accident source term under the design extension condition.

[0163] In order to facilitate understanding of the method for determining the maximum 2-hour accident source item under the design expansion condition provided in the embodiment of the present application, it is explained below in conjunction with a specific embodiment.

[0164] like Figure 7 As shown, the method for determining the maximum 2-hour accident source item under the design extension condition provided in the embodiment of the present application may include the following contents.

[0165] (1) Nuclide group release share T t (i.e. the first release share group) and initial mass M (i.e. the second release share group) statistics

[0166] According to the nuclide grouping (K groups in total), according to the types of radioactive material release under the accident condition (i.e. the first accident) (n groups), the types of radioactive materials that should be considered in each nuclide group are counted. Based on the entire accident duration, the change curve of the proportion of each group of materials released to the environment relative to the initial mass of the core over time f t =[f 1t ,f 2t ,……,f nt ]

[0167] (i.e. the first variation curve) and the initial mass of the core m = [m1, m2, ..., m n ], determine the release share (i.e., the first release share group) and initial mass (i.e., the first initial mass group) of radioactive substances that should be considered in each nuclide group. The specific method is: initialize the release share T that should be considered for the radionuclide group t = [] (i.e., the second release share group); initial mass M = [] (i.e., the second initial mass group). For radioactive material j, compare the nuclides in nuclide group k (i.e., the kth nuclide group). If radioactive material j includes nuclides in nuclide group k (i.e., the kth nuclide group), then the release share of the jth radioactive material should be considered in the release share of group k (i.e., the first release share group of group k), i.e., T kt =[T kt , f jt ],M k =[M k , mj ]. The radioactive material release share to be considered for each nuclide group is counted in turn to obtain T and M. It should be noted that for radioactive material j, it may include more than one nuclide, such as C S I, including two nuclides, Cs and I, both of which belong to the two nuclides groups of halogen (I) and alkali metal (Cs), therefore, the release share of CsI needs to be considered in both groups.

[0168] (2) Determine the release share F of each nuclide group during the entire accident period t (i.e. the total release fraction curve).

[0169] For nuclide group k, the nuclide release share T kt (i.e. the first release share group) and the initial core mass M k (i.e. the first initial mass group), according to the mass distribution of the substance, the release share F of the k nuclide group over time is calculated kt .

[0170] F kt =∑(T kt ·M k ) / ∑(M k )(i.e. formula (1))

[0171] (3) The cumulative release fraction F of each nuclide group every 2 hours is intercepted T (i.e. cumulative release share).

[0172] T: Starting from the release time t0 of the accident, every 0.01 hour is used as the interval until 2 hours before the end of the release as the starting time T0 of the 2-hour source term, that is, the starting time corresponding to the T period is recorded as T0 = (t0, t0 + 0.01, t0 + 0.02, ... t e -2), in h, the end time Te = T0 + 2, in h. Intercept the cumulative release share F of each nuclide group every 2 hours T =F Te -F T0 .

[0173] The release share of the nuclide group corresponds to the release share of the nuclide;

[0174] (4) Calculate the environmental release source term Q every 2 hours T .

[0175] Combined with the core nuclide N and the accumulation of nuclides S (i.e. the accumulation of nuclides), the ratio of different chemical forms of nuclides C, the initial release time T0, the nuclide release fraction F T , considering the decay e of the nuclide from the initial time of the accident to the start time of release T0 -λ·T0 , determine the environmental release source term Q every 2 hours TFor nuclide n:

[0176]

[0177] (5) Calculate the effective dose D T (ie the first effective dose).

[0178] The source term Q is calculated by taking the maximum value of the atmospheric diffusion factor X / Q at the boundary of the non-residential area for 2 hours, combining the dose conversion factors of each nuclide (including the air immersion external radiation dose conversion factor DFA and the inhalation internal radiation dose conversion factor DFI) and the breathing rate BR. T DA by air immersion T and inhalation internal irradiation DI T The effective dose received by the route D T .

[0179]

[0180] D T =DA T +DI T (i.e. formula (5))

[0181] (6) Filter the maximum 2-hour source item Sa_max2h corresponding to accident sequence A (i.e., the first accident).

[0182] Effective dose D T Sort them and select the dose consequence Da_max2h with the largest effective dose, and its corresponding source item is used as the maximum 2-hour source item Sa_max2h of accident sequence A.

[0183] (7) Calculate the accident sequences B, C, ... in turn to obtain the maximum 2-hour consequences Db_max2h, Dc_max2h, ... and the corresponding source items Sb_max2h, Sc_max2h, .... According to the size of the maximum 2-hour accident consequences Da_max2h, Db_max2h, ... of different sequences, select the 2-hour accident source item corresponding to the accident sequence with the largest consequence as the maximum 2-hour accident source item (i.e., the maximum 2-hour accident source item under the design expansion condition), and further analyze its feasibility as the basis for the division of non-residential areas.

[0184] Based on the same concept, the embodiment of the present application also provides a device for determining a maximum 2-hour source term. The device for determining a maximum 2-hour source term provided by the embodiment of the present application is described below in conjunction with the accompanying drawings.

[0185] Example 3

[0186] like Figure 8As shown, the maximum 2-hour source term determination device 800 provided in the embodiment of the present application can be applied to the first accident of a nuclear power plant. The maximum 2-hour source term determination device 800 may include a first acquisition module 810, a first determination module 820, a second determination module 830 and a third determination module 840.

[0187] The first acquisition module 810 is used to acquire, for each nuclide group in the K nuclide groups under the first accident, M cumulative release shares of the nuclide group corresponding to each other within 2 hours from the start time of the M targets, so as to obtain M×K cumulative release shares, where M and K are both positive integers;

[0188] A first determination module 820 is connected to the first acquisition module 810 and is used to determine, for each of the M×K cumulative release shares, an environment release source item corresponding to the cumulative release share, so as to obtain M×K environment release source items;

[0189] The second determination module 830 is connected to the first determination module 820, and is used to determine the first effective dose corresponding to each of the M×K environmental release source terms, so as to obtain M×K first effective doses;

[0190] The third determination module 840 is connected to the second determination module 830 and is used to determine the maximum 2-hour source term of the first accident according to the M×K first effective doses.

[0191] According to the maximum 2-hour source term determination device provided in the embodiment of the present application, by considering the M×K cumulative release shares corresponding to the K groups of nuclides, the cumulative release shares can be obtained more comprehensively; by gradually converting the cumulative release shares into environmental release source terms and the first effective dose, the maximum 2-hour source term of the first accident is finally determined according to the first effective dose, which reduces the dependence on the uniform release assumption and the simplified model, and can improve the accuracy of the determination of the maximum 2-hour source term of the first accident, thereby providing a possibility for subsequently improving the accuracy of the determination of the maximum 2-hour accident source term under the design expansion conditions of the nuclear power plant.

[0192] In some implementations, the maximum 2-hour source term determining device 800 further includes:

[0193] A second acquisition module, connected to the first acquisition module, is used to acquire K target parameter groups corresponding to K groups of nuclides under the first accident;

[0194] The first acquisition module 810 is specifically used for:

[0195] According to the target parameter groups corresponding to the nuclide groups, M corresponding cumulative release shares of the nuclide groups within 2 hours from the start time of the M targets are determined.

[0196] In some embodiments, the target parameter group includes a first release fraction group and a first initial mass group.

[0197] The second acquisition module can be specifically used for:

[0198] Get the second release share group and the second initial quality group, where both the second release share group and the second initial quality group are empty arrays;

[0199] For each nuclide group in the K groups of nuclides under the first accident, determine the J types of radioactive materials to which the P types of nuclides in the nuclide group belong respectively, so as to obtain K×J types of radioactive materials;

[0200] For each nuclide group in the K nuclide groups under the first accident, J first change curves corresponding to J types of radioactive materials are stored in the second release share group to obtain the first release share group, so as to obtain K first release share groups;

[0201] For each nuclide group in the K nuclide groups under the first accident, J initial masses of J types of radioactive materials are stored one by one into the second initial mass group to obtain the first initial mass group, so as to obtain K first initial mass groups.

[0202] In some implementations, the first acquisition module 810 is specifically configured to:

[0203] Determine the total release share curve of the nuclide group during the first accident duration according to the target parameter group corresponding to the nuclide group;

[0204] According to the total release share curve, determine the M corresponding cumulative release shares of the nuclide groups within 2 hours from the starting time of the M targets.

[0205] In some embodiments, the target parameter group includes a first release share group and a first initial mass group, the first release share group includes J first change curves corresponding to J types of radioactive materials one by one, the first initial mass group includes J initial masses corresponding to J types of radioactive materials one by one, and the first change curve is a curve of the change of the release share of the radioactive material to the environment relative to the initial mass of the core over time during the first accident;

[0206] The first acquisition module 810 is specifically used for:

[0207] Substitute the J first change curves and the J initial masses into formula (1) to calculate and obtain the total release share curve of the nuclide group during the first accident duration;

[0208] Formula (1) includes:

[0209]

[0210] Among them, Fk represents the total release fraction curve of the k-th nuclide group during the first accident duration; T kj represents the j-th first change curve corresponding to the k-th nuclide group; M kj represents the j-th initial mass corresponding to the k-th nuclide group; j ≤ J, k ≤ K.

[0211] In some embodiments, the first acquisition module 810 is specifically configured to:

[0212] For each target start time among the M target start times, substitute it and its corresponding target end time into formula (1) respectively to obtain the first release fraction corresponding to the target start time and the second release fraction corresponding to the target end time, so as to obtain M first release fractions and M second release fractions, and the target end time is the time 2 hours later than its corresponding target start time;

[0213] For each target start time among the M target start times, determine the difference between the corresponding second release fraction and the first release fraction as the cumulative release fraction, so as to obtain M cumulative release fractions corresponding one by one for the nuclide group within 2 hours starting from the M target start times.

[0214] In some embodiments, the first target start time among the M target start times is the start release time of the first accident, and the difference between the m-th target start time and the (m + 1)-th target start time is 0.01 hour, 0 ≤ m < M, and m is an integer.

[0215] In some embodiments, the environmental release source term includes the activities of N nuclides, where N is a positive integer;

[0216] The first determination module 820 is specifically configured to:

[0217] Obtain the start release time of the first accident, the N nuclides corresponding to the cumulative release fraction, and the N nuclide parameter groups corresponding one by one to the N nuclides. The nuclide parameter group includes nuclide inventory, nuclide different chemical form ratios, and nuclide decay coefficients;

[0218] For each nuclide among the N nuclides, substitute the start release time, the cumulative release fraction, and the nuclide parameter group corresponding to the nuclide into formula (2) for calculation to obtain the activity of the nuclide, so as to obtain the activities of the N nuclides;

[0219] Formula (2) includes:

[0220]

[0221] where, T0 represents the target start time; n represents the n-th nuclide; In the figure, it represents the activity of the nth nuclide released from the target starting time T0; S n Indicates the nuclide stock of the nth nuclide; It represents the cumulative release share of the nth nuclide within 2 hours from the target starting time T0; represents the nuclide decay coefficient of the nth nuclide from the start of the first accident to the target start time T0; C n It represents the ratio of different chemical forms of the nth nuclide.

[0222] In some embodiments, the environmental release source term includes the activities of N nuclides;

[0223] The second determining module 830 is specifically configured to:

[0224] Obtain the maximum value of the atmospheric diffusion factor, the respiration rate, and N conversion factors corresponding to the activities of N types of nuclides, including the conversion factor of air immersion external radiation dose and the conversion factor of inhalation internal radiation dose;

[0225] Substitute the N air immersion external radiation dose conversion factors corresponding to the maximum value of the atmospheric diffusion factor and the activity of the N nuclides into formula (3) to calculate the air immersion external radiation dose;

[0226] Formula (3) includes:

[0227]

[0228] in, It represents the air immersion external exposure corresponding to the environmental release source term released from the target starting time T0; It represents the activity of the nth nuclide released from the target starting time T; Indicates the maximum atmospheric diffusion factor; DFA n It represents the air immersion external radiation dose conversion factor corresponding to the activity of the nth nuclide;

[0229] Substitute the N inhalation internal radiation dose conversion factors corresponding to the maximum value of the atmospheric diffusion factor, the respiration rate, and the activity of the N nuclides into formula (4) to calculate the inhalation internal radiation dose;

[0230] Formula (4) includes:

[0231]

[0232] in, represents the inhaled internal exposure corresponding to the environmental release source term released at the target starting time T0; BR represents the breathing rate; DFI n The conversion factor of inhalation internal radiation dose corresponding to the activity of the nth nuclide;

[0233] Substitute the air immersion external exposure and the inhalation internal exposure into formula (5) to calculate the first effective dose corresponding to the environmental release source term;

[0234] Formula (5) includes:

[0235]

[0236] in, Represents the first effective dose corresponding to the environmental release source term.

[0237] In some implementations, the third determination module 840 may be specifically configured to:

[0238] The environmental release source item corresponding to the first effective dose with the largest value among the M×K first effective doses is determined as the maximum 2-hour source item of the first accident.

[0239] In some implementations, the maximum 2-hour source term determining device 800 may further include:

[0240] An obtaining module is used to sort the M×K first effective doses according to numerical values ​​to obtain a first effective dose sequence;

[0241] The fifth determination module is used to determine the first effective dose with the largest value among M×K first effective doses in the first effective dose sequence.

[0242] The maximum 2-hour source item determination device provided in the embodiment of the present application can be used to execute the maximum 2-hour source item determination method, that is, it has the beneficial effects and implementation methods of the maximum 2-hour source item determination method provided in Example 1 of the present application. For details, please refer to the specific description of the maximum 2-hour source item determination method in the above Example 1, which will not be repeated in this embodiment.

[0243] Based on the same concept, the embodiment of the present application also provides a system for determining the maximum 2-hour accident source term under the design expansion condition. The system for determining the maximum 2-hour accident source term under the design expansion condition provided by the embodiment of the present application is described below in conjunction with the accompanying drawings.

[0244] Example 4

[0245] like Fig. 9 As shown, the system for determining the maximum 2-hour accident source item under the design extension condition provided in the embodiment of the present application can be applied to a nuclear power plant, and the system 1000 for determining the maximum 2-hour accident source item under the design extension condition may include a device 900 for determining the maximum 2-hour accident source item under the design extension condition, and a device 800 for determining the maximum 2-hour source item as in any one of Embodiment 3.

[0246] The maximum 2-hour source term determining device 800 is used to determine the maximum 2-hour source terms of multiple first accidents, and determine the first effective dose corresponding to the maximum 2-hour source term of each first accident among the maximum 2-hour source terms of the multiple first accidents as the second effective dose;

[0247] The device 900 for determining the maximum 2-hour accident source item under the design expansion condition comprises:

[0248] The fourth determination module 910 is connected to the maximum 2-hour source term determination device, and is used to determine the maximum 2-hour source term of the first accident corresponding to the second effective dose with the largest value as the maximum 2-hour accident source term under the design expansion condition.

[0249] According to the determination system of the maximum 2-hour accident source term under the design extension condition provided by the embodiment of the present application, the maximum 2-hour source term of multiple first accidents is determined by the maximum 2-hour source term determination method of any one of the embodiments, and the first effective dose corresponding to the maximum 2-hour source term of each first accident in the maximum 2-hour source terms of multiple first accidents is determined as the second effective dose; then the maximum 2-hour source term of the first accident corresponding to the second effective dose with the largest value can be determined as the maximum 2-hour accident source term under the design extension condition. In this way, the embodiment of the present application can accurately and reasonably determine the maximum 2-hour accident source term under the design extension condition.

[0250] The system for determining the maximum 2-hour accident source item under the design expansion condition provided in the embodiment of the present application can be used to execute the method for determining the maximum 2-hour accident source item under the design expansion condition, that is, it has the beneficial effects and implementation methods of the method for determining the maximum 2-hour accident source item under the design expansion condition provided in Example 2 of the present application. For details, please refer to the specific description of the method for determining the maximum 2-hour accident source item under the design expansion condition in the above Example 2, which will not be repeated in this embodiment.

[0251] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present application, but the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of the present application, and these modifications and improvements are also considered to be within the scope of protection of the present application.

Claims

1. A method for determining a maximum 2-hour source term, characterized in that: Applied to the first accident of a nuclear power plant, the method comprises: For each nuclide group in the K nuclide groups under the first accident, obtain the M cumulative release shares of the nuclide group within 2 hours from the start time of the M targets, so as to obtain M×K cumulative release shares, where M and K are both positive integers; For each of the M×K cumulative release shares, determine the environmental release source item corresponding to the cumulative release share to obtain M×K environmental release source items; For each of the M×K environmental release source terms, determine the first effective dose corresponding to the environmental release source term to obtain M×K first effective doses; Based on the M×K first effective doses, the maximum 2-hour source term of the first accident is determined.

2. The method according to claim 1, characterized in that Before obtaining the M cumulative release shares of the nuclide groups corresponding to each other within 2 hours from the start time of the M targets, the method further includes: Obtain K target parameter groups corresponding to K groups of nuclides under the first accident; The method of obtaining the M cumulative release shares of the nuclide groups corresponding to each other within 2 hours from the start time of the M targets includes: According to the target parameter groups corresponding to the nuclide groups, M corresponding cumulative release shares of the nuclide groups within 2 hours from the start time of the M targets are determined.

3. The method according to claim 2, characterized in that The target parameter group includes a first release share group and a first initial mass group, The step of obtaining K target parameter groups corresponding to K groups of nuclides under the first accident includes: Acquire a second released share group and a second initial quality group, wherein the second released share group and the second initial quality group are both empty arrays; For each nuclide group in the K groups of nuclides under the first accident, determine the J types of radioactive materials to which the P types of nuclides in the nuclide group belong respectively, so as to obtain K×J types of radioactive materials; For each nuclide group in the K nuclide groups under the first accident, J first change curves corresponding to J types of radioactive materials are stored in the second release share group to obtain the first release share group, so as to obtain K first release share groups; For each nuclide group in the K nuclide groups under the first accident, J initial masses of J types of radioactive materials are stored one by one into the second initial mass group to obtain the first initial mass group, so as to obtain K first initial mass groups.

4. The method according to claim 2, characterized in that: The method of determining the M cumulative release shares of the nuclide groups corresponding to the target parameter groups within 2 hours from the start time of the M targets according to the nuclide groups includes: Determine the total release share curve of the nuclide group during the first accident duration according to the target parameter group corresponding to the nuclide group; According to the total release share curve, M cumulative release shares of the nuclide groups corresponding to each other within 2 hours from the start time of the M targets are determined.

5. The method according to claim 4, characterized in that The target parameter group includes a first release share group and a first initial mass group, the first release share group includes J first change curves corresponding to J types of radioactive materials one by one, the first initial mass group includes J initial masses corresponding to J types of radioactive materials one by one, and the first change curve is a curve of the change of the release share of radioactive materials to the environment relative to the initial mass of the core over time during the first accident; Determining the total release fraction curve of the nuclide group during the first accident duration according to the target parameter group corresponding to the nuclide group includes: Calculating by substituting J first change curves and J initial masses into formula (1) to obtain the total release fraction curve of the nuclide group during the first accident duration; The formula (1) includes: Among them, F k represents the total release share curve of the kth nuclide group during the first accident duration; T kj represents the jth first variation curve corresponding to the kth nuclide group; M kj Indicates the jth initial mass corresponding to the kth nuclide group; j≤J, k≤K.

6. The method according to claim 5, characterized in that Determining the M cumulative release fractions corresponding one by one within 2 hours starting from M target start times for the nuclide group according to the total release fraction curve includes: For each target start time among the M target start times, substituting it and its corresponding target end time into the formula (1) respectively to obtain the first release fraction corresponding to the target start time and the second release fraction corresponding to the target end time, so as to obtain M first release fractions and M second release fractions, where the target end time is the time 2 hours later than its corresponding target start time; For each target start time among the M target start times, determining the difference between the corresponding second release fraction and the first release fraction as the cumulative release fraction, so as to obtain the M cumulative release fractions corresponding one by one within 2 hours starting from the M target start times for the nuclide group.

7. The method according to any one of claims 1 to 6, characterized in that The first target start time among the M target start times is the start release time of the first accident, and the difference between the m-th target start time and the (m + 1)-th target start time is 0.01 hours, 0 ≤ m < M, and m is an integer.

8. The method according to claim 1, characterized in that The environmental release source term includes the activities of N nuclides, and N is a positive integer; Determining the environmental release source term corresponding to the cumulative release fraction includes: Obtaining the start release time of the first accident, the N nuclides corresponding to the cumulative release fraction, and the N nuclide parameter groups corresponding one by one to the N nuclides, where the nuclide parameter group includes nuclide inventory, proportion of different chemical forms of the nuclide, and nuclide decay coefficient; For each nuclide among the N nuclides, substituting the start release time, the cumulative release fraction, and the nuclide parameter group corresponding to the nuclide into formula (2) for calculation to obtain the activity of the nuclide, so as to obtain the activities of the N nuclides; The formula (2) includes: Where T0 represents the target starting time; n represents the nth nuclide; It represents the activity of the nth nuclide released from the target starting time T0; S n Indicates the nuclide stock of the nth nuclide; It represents the cumulative release share of the nth nuclide within 2 hours from the target starting time T0; represents the nuclide decay coefficient of the nth nuclide from the start of the first accident to the target start time T0; C n It represents the ratio of different chemical forms of the nth nuclide.

9. The method according to claim 1, characterized in that: The environmental release source term includes the activities of N nuclides; Determining the first effective dose corresponding to the environmental release source term includes: Obtaining the maximum value of the atmospheric dispersion factor, the breathing rate, and the N conversion factors corresponding one by one to the activities of the N nuclides, where the conversion factors include the air submersion external exposure dose conversion factor and the inhalation internal exposure dose conversion factor; Substituting the maximum value of the atmospheric dispersion factor and the N air submersion external exposure dose conversion factors corresponding one by one to the activities of the N nuclides into formula (3) for calculation to obtain the air submersion external exposure amount; The formula (3) includes: in, It represents the air immersion external exposure corresponding to the environmental release source term released from the target starting time T0; Indicates the activity of the nth nuclide released from the target starting time T0; Indicates the maximum atmospheric diffusion factor; DFA n It represents the air immersion external radiation dose conversion factor corresponding to the activity of the nth nuclide; Substituting the maximum value of the atmospheric dispersion factor, the breathing rate, and the N inhalation internal exposure dose conversion factors corresponding one by one to the activities of the N nuclides into formula (4) for calculation to obtain the inhalation internal exposure amount; The formula (4) includes: in, represents the inhaled internal exposure corresponding to the environmental release source term released at the target starting time T0; BR represents the breathing rate; DFI n The conversion factor of inhalation internal radiation dose corresponding to the activity of the nth nuclide; Substituting the air submersion external exposure amount and the inhalation internal exposure amount into formula (5) for calculation to obtain the first effective dose corresponding to the environmental release source term; The formula (5) includes: in, Represents the first effective dose corresponding to the environmental release source term.

10. The method according to claim 1, characterized in that Determining the maximum 2-hour source term for the first accident based on M×K first effective doses includes: The environmental release source item corresponding to the first effective dose with the largest value among the M×K first effective doses is determined as the maximum 2-hour source item of the first accident.

11. The method according to claim 10, characterized in that Before determining the environmental release source term corresponding to the first effective dose with the largest value among the M×K first effective doses as the maximum 2-hour source term for the first accident, the method further includes: Sort the M×K first effective doses according to their numerical values ​​to obtain a first effective dose sequence; A first effective dose having the largest value among M×K first effective doses is determined from the first effective dose sequence.

12. A method for determining the maximum 2-hour accident source term under design expansion conditions, characterized in that: Applied to a nuclear power plant, the method comprises: The method for determining the maximum 2-hour source term of an accident according to any one of claims 1 to 11, determining a plurality of maximum 2-hour source terms of first accidents, and determining a first effective dose corresponding to each maximum 2-hour source term of the first accident among the plurality of maximum 2-hour source terms of first accidents as a second effective dose; The maximum 2-hour source term of the first accident corresponding to the second effective dose with the largest value is determined as the maximum 2-hour accident source term under the design expansion condition.

13. A device for determining a maximum 2-hour source term, characterized in that: Applied to a nuclear power plant, the device comprises: The first acquisition module is used to obtain, for each nuclide group in the K nuclide groups under the first accident, M cumulative release shares of the nuclide group within 2 hours from the start time of the M targets, so as to obtain M×K cumulative release shares, where M and K are both positive integers; A first determination module, connected to the first acquisition module, is used to determine, for each of the M×K cumulative release shares, an environment release source item corresponding to the cumulative release share, so as to obtain M×K environment release source items; a second determination module, connected to the first determination module, for determining a first effective dose corresponding to each of the M×K environmental release source terms, so as to obtain M×K first effective doses; The third determination module is connected to the second determination module and is used to determine a maximum 2-hour source term of the first accident according to M×K first effective doses.

14. The device according to claim 13, characterized in that The device also includes: A second acquisition module, connected to the first acquisition module, is used to acquire K target parameter groups corresponding to K groups of nuclides under a first accident; The first acquisition module is specifically used to: According to the target parameter groups corresponding to the nuclide groups, M corresponding cumulative release shares of the nuclide groups within 2 hours from the start time of the M targets are determined.

15. The device according to claim 13, characterized in that The environmental release source term includes the activities of N nuclides, where N is a positive integer; The first determining module is specifically configured to: Obtaining the release start time of the first accident, N nuclides corresponding to the cumulative release share, and N nuclide parameter groups corresponding to the N nuclides one by one, wherein the nuclide parameter groups include nuclide accumulation, ratios of different chemical forms of nuclides, and nuclide decay coefficients; For each of the N nuclides, the release start time, the cumulative release fraction and the nuclide parameter group corresponding to the nuclide are substituted into formula (2) to calculate and obtain the activity of the nuclide, so as to obtain the activities of the N nuclides; The formula (2) includes: Where T0 represents the target starting time; n represents the nth nuclide; In the figure, it represents the activity of the nth nuclide released from the target starting time T0; S n Indicates the nuclide stock of the nth nuclide; It represents the cumulative release share of the nth nuclide within 2 hours from the target starting time T0; represents the nuclide decay coefficient of the nth nuclide from the start of the first accident to the target start time T0; C n It represents the ratio of different chemical forms of the nth nuclide.

16. The device according to claim 13, characterized in that The environmental release source term includes the activities of N nuclides; The second determining module is specifically used to: Obtaining N conversion factors corresponding to the maximum value of the atmospheric diffusion factor, the breathing rate, and the activities of the N nuclides, wherein the conversion factors include an air immersion external radiation dose conversion factor and an inhalation internal radiation dose conversion factor; Substitute the maximum value of the atmospheric diffusion factor and the N air immersion external radiation dose conversion factors corresponding to the activities of the N types of nuclides into formula (3) for calculation to obtain the air immersion external radiation dose; The formula (3) includes: in, It represents the air immersion external exposure corresponding to the environmental release source term released from the target starting time T0; It represents the activity of the nth nuclide released from the target starting time T; Indicates the maximum atmospheric diffusion factor; DFA n It represents the air immersion external radiation dose conversion factor corresponding to the activity of the nth nuclide; Substitute the N inhalation internal radiation dose conversion factors corresponding to the maximum value of the atmospheric diffusion factor, the breathing rate, and the activities of the N types of nuclides into formula (4) for calculation to obtain the inhalation internal radiation dose; The formula (4) includes: in, represents the inhaled internal exposure corresponding to the environmental release source term released at the target starting time T0; BR represents the breathing rate; DFI n The conversion factor of inhalation internal radiation dose corresponding to the activity of the nth nuclide; Substituting the air immersion external exposure and the inhalation internal exposure into formula (5) for calculation, the first effective dose corresponding to the environmental release source term is obtained; The formula (5) includes: in, Represents the first effective dose corresponding to the environmental release source term.

17. A system for determining the maximum 2-hour accident source term under design expansion conditions, characterized in that: Applied to a nuclear power plant, the system comprises: The determination device of the maximum 2-hour accident source term under the design expansion condition, and The maximum 2-hour source term determination device according to any one of claims 13 to 16; The maximum 2-hour source term determining device is used to determine the maximum 2-hour source terms of multiple first accidents, and determine the first effective dose corresponding to the maximum 2-hour source term of each first accident among the maximum 2-hour source terms of the multiple first accidents as the second effective dose; The device for determining the maximum 2-hour accident source item under the design expansion condition comprises: The fourth determination module is connected to the maximum 2-hour source term determination device, and is used to determine the maximum 2-hour source term of the first accident corresponding to the second effective dose with the largest value as the maximum 2-hour accident source term under the design expansion condition.

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