A method and system for simulating the hydrogen risk inside the containment vessel during a severe reactor accident

Abstract

The present disclosure provides a method and system for simulating the hydrogen risk inside a containment during a severe reactor accident, which relates to the technical field of hydrogen risk simulation. The method includes, for a severe accident sequence, obtaining the severe reactor accident data, analyzing the severe accident process, and obtaining the hydrogen production source term parameters required for three-dimensional analysis; establishing a three-dimensional analysis model according to the actual spatial dimensions of the containment, setting the key node parameters, modeling and meshing the nodes, and dividing the containment into multiple compartment areas; adopting super-real-time simulation and assuming the occurrence of a severe accident, using the three-dimensional analysis model to analyze the hydrogen concentration in each compartment area of the containment, determining the risk level of each area at this hydrogen concentration according to the judgment criteria, and displaying it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the containment of a nuclear power plant. The present disclosure can calculate the hydrogen concentration in different areas of each compartment of the containment and effectively predict the hydrogen risk.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hydrogen risk simulation, and in particular, to a method and system for simulating hydrogen risk in a containment during a severe reactor accident. Background Art

[0002] The statements in this section merely provide background technical information related to the present disclosure and do not necessarily constitute prior art.

[0003] In a severe accident of a pressurized water reactor nuclear power plant, after the core is uncovered, the fuel will heat up and melt. After the fuel cladding heats up, it will start to react with the water and steam in the reactor, generating a large amount of hydrogen. This hydrogen will be discharged into the containment through breaks and valves, etc. In addition, if the lower head of the pressure vessel fails and the core melt enters the containment, the zirconium that enters the gas space of the containment may oxidize briefly to produce hydrogen, and a large amount of hydrogen will be generated by the reaction of the melt with concrete (MCCI). Since the containment has many compartments, each compartment is distributed at different locations, and the large amount of hydrogen generated in the reactor will be distributed in the containment compartments, and there are significant differences in hydrogen concentration at different locations. According to research and analysis, if the hydrogen concentration accumulated in the containment exceeds the limit, it may react with oxygen, thus posing an explosion risk. The over-temperature and over-pressure generated by the explosion pose a threat to the integrity of the containment, and may even cause the containment to fail, resulting in a large release of radioactive substances into the environment, which will cause very serious harm to the public and the environment.

[0004] In the development of nuclear power, safety is of utmost importance, and effective simulation of accident consequences is an important concern. The phenomena of severe accidents are complex, and multiple high-precision simulation models are required to analyze the development process of severe accidents and determine the phenomena during the accident. Hydrogen risk, as an important factor, occupies an important position in the analysis of severe accidents. The combustion state of hydrogen can be divided into slow combustion (slow diffusion combustion), fast combustion (fast turbulent combustion or flame acceleration), and deflagration. Generally speaking: when the hydrogen volume concentration is between the lower flammability limit (4%) and below the flame propagation boundary (8%), slow combustion will occur. When combustion spreads subsonically into a mixture of hydrogen, steam, and air (hydrogen concentration is between 8% - 14%), under certain conditions, the mixture gas will undergo fast combustion, and this may further lead to the transition from fast combustion to deflagration (DDT). When combustion spreads supersonically in a mixture of hydrogen, steam, and air (hydrogen concentration exceeds 14%), deflagration may occur. The occurrence of deflagration forms a relatively high pressure pulse in a very short time, and the resulting pressure load threatens the integrity of the containment.

[0005] The existing hydrogen risk prediction method usually uses a lumped procedure for calculation and analysis to obtain the hydrogen concentration in the compartments inside the containment, without being combined with a three-dimensional simulation system. As a result, it is impossible to perform real-time simulation or super-real-time simulation on the three-dimensional hydrogen risk inside the containment during an accident to provide hydrogen analysis results. Summary of the Invention

[0006] To solve the above problems, the present disclosure proposes a method and system for simulating the hydrogen risk inside the containment during a severe reactor accident. By performing real-time simulation or super-real-time simulation on the three-dimensional hydrogen risk inside the containment during an accident, hydrogen analysis results are provided and displayed in real time on the three-dimensional simulation screen, thereby providing important support for accident status evaluation, accident management, and emergency decision-making.

[0007] According to some embodiments, the present disclosure adopts the following technical solutions:

[0008] A method for simulating the hydrogen risk inside the containment during a severe reactor accident, comprising:

[0009] Based on typical operating conditions, identify the initiating event and set the severe accident sequence;

[0010] For the severe accident sequence, obtain the severe reactor accident data, conduct a severe accident process analysis, and obtain the hydrogen production source term parameters required for three-dimensional analysis;

[0011] Taking the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set the key node parameters, model the nodes and perform mesh division, and divide the containment into multiple compartment areas;

[0012] Adopt super-real-time simulation and assume that a severe accident occurs. Using the three-dimensional analysis model, analyze the hydrogen concentration in each compartment area of the containment, determine the risk level of each area at this hydrogen concentration according to the judgment criteria, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the nuclear power plant containment.

[0013] According to some embodiments, the present disclosure adopts the following technical solutions:

[0014] A system for simulating the hydrogen risk inside the containment during a severe reactor accident, comprising:

[0015] A parameter acquisition module, configured to identify the initiating event and set the severe accident sequence based on typical operating conditions;

[0016] For the severe accident sequence, obtain the severe reactor accident data, conduct a severe accident process analysis, and obtain the hydrogen production source term parameters required for three-dimensional analysis;

[0017] A three-dimensional model construction module is used to take the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set the key parameters of the nodes, model and mesh the nodes, and divide the containment into multiple compartment areas;

[0018] A hydrogen concentration calculation module is used to adopt super-real-time simulation and assume the occurrence of a severe accident, use the three-dimensional analysis model to analyze the hydrogen concentration in each compartment area of the containment, determine the risk level of each area at this hydrogen concentration according to the judgment criteria, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the nuclear power plant containment.

[0019] Compared with the prior art, the beneficial effects of the present disclosure are as follows:

[0020] In a method for simulating the hydrogen risk inside the containment during a severe accident of a reactor according to the present disclosure, by using the method of real-time simulation of the three-dimensional hydrogen risk inside the containment during a severe accident of the reactor, for a severe accident sequence, obtaining the severe accident data of the reactor, analyzing the severe accident process, and obtaining the hydrogen production source term parameters required for three-dimensional analysis; taking the containment as the hydrogen analysis area, establishing a three-dimensional analysis model according to the actual spatial dimensions of the containment, setting the key parameters of the nodes, modeling and meshing the nodes, and dividing the containment into multiple compartment areas; after obtaining the accident process results, the hydrogen analysis module uses three-dimensional calculation. The advantage of this method compared with two-dimensional simulation is that it can give the hydrogen concentration in different areas of each compartment of the containment, and the analysis results are more accurate; covering all the compartment areas of the containment, and making a reasonable mesh division of the nodes, meeting the needs of three-dimensional hydrogen analysis, and being able to ensure good operation speed and analysis accuracy.

[0021] Real-time prediction of the hydrogen risk inside the nuclear power plant containment provides support for taking mitigation strategies; accurately obtaining the hydrogen concentration at different compartment positions, i.e., in three-dimensional space; implemented by combining the simulation server hardware and the three-dimensional model analysis software, and the simulation effect is intuitive and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings forming a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure.

[0023] Figure 1 It is a system architecture diagram of a method for simulating the hydrogen risk inside the containment during a severe accident of a reactor according to the present disclosure;

[0024] Figure 2 It is a schematic diagram of a three-dimensional simulation display screen simulation according to the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present disclosure will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present disclosure belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Embodiment 1

[0029] In one embodiment of the present disclosure, a method for simulating the hydrogen risk in a containment vessel during a severe reactor accident is provided, including:

[0030] Step 1: Based on typical operating conditions, identify the initiating event and set the severe accident sequence;

[0031] For the severe accident sequence, obtain the severe reactor accident data, conduct an analysis of the severe accident process, and obtain the hydrogen production source term parameters required for three-dimensional analysis;

[0032] Step 2: Take the containment vessel as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment vessel, set the key node parameters, model and mesh the nodes, and divide the containment vessel into multiple compartment areas;

[0033] Step 3: Adopt super-real-time simulation and assume that a severe accident occurs. Use the three-dimensional analysis model to analyze the hydrogen concentration in each compartment area of the containment vessel. According to the judgment criteria, determine the risk level of each area at this hydrogen concentration and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk in the containment vessel of the nuclear power plant.

[0034] As an embodiment, the present application provides a method for simulating the hydrogen risk inside the containment during a severe reactor accident. This method realizes the three-dimensional hydrogen risk simulation by combining hardware and software. In terms of hardware, it mainly includes a simulation server and a three-dimensional simulation display screen. The software part includes the acquisition and analysis of severe accident data and the analysis of the three-dimensional hydrogen model. The simulation server is equipped with various analysis software, which can store, analyze, and display in the three-dimensional simulation screen. The acquisition and analysis of severe accident data are combined with the analysis of the three-dimensional hydrogen model for calculation. First, the accident process analysis is carried out through the severe accident data acquisition and analysis software to obtain the source term parameters required for three-dimensional analysis. Then, the three-dimensional hydrogen model analysis is called to obtain the three-dimensional results of the hydrogen concentration at different compartment positions inside the containment. The specific implementation methods include:

[0035] Step 1: Conduct the acquisition and analysis of severe accident data, which mainly includes: based on typical operating conditions, identify the initiating event, obtain the effectiveness of various mitigation measures, set the accident sequence, and for the accident sequence, use severe accident software to carry out analysis and calculation to obtain the process of the accident sequence, and obtain the hydrogen production situation during the accident in real time, including the release of mass and energy such as water and water vapor, and the hydrogen production rate, etc.

[0036] It also includes: including the accident process time, whether MCCI occurs, and the hydrogen mass, which provides inputs for subsequent three-dimensional hydrogen analysis.

[0037] Specifically, for the severe accident sequence, use severe accident software to carry out analysis and calculation to obtain the process of the accident sequence. The selection of the severe accident sequence is usually obtained based on the results of the probabilistic safety analysis of nuclear power plants, such as existing LOCA accident conditions, etc.

[0038] Step 2: Take the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial size of the containment, set the key node parameters, conduct node modeling and mesh generation, and divide the containment into multiple compartment areas;

[0039] The three-dimensional modeling of the containment, the main process is to carry out node modeling according to the shape and size parameters of the containment designed by the power plant, etc., which should cover all the containment compartment areas, and conduct reasonable mesh generation for the nodes to meet the needs of three-dimensional hydrogen analysis and ensure good operation speed and analysis accuracy.

[0040] Specifically, the established three-dimensional model is divided based on the volume size of the containment compartments. Each compartment can be divided into many nodes according to the volume size. For example, a compartment with a particularly small volume can be divided into thousands of nodes (areas), while a compartment with a particularly large volume can be divided into thousands to tens of thousands of nodes.

[0041] Step 3: Adopt super-real-time simulation and assume a severe accident occurs. Use a three-dimensional analysis model to analyze the hydrogen concentration in each compartment area of the containment. According to the judgment criteria, determine the risk level at which each area is located under this hydrogen concentration, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the nuclear power plant containment.

[0042] Specifically, taking the inside of the containment as the hydrogen analysis area, use a three-dimensional hydrogen calculation program for three-dimensional simulation. Establish a three-dimensional analysis model according to the actual spatial dimensions of the containment and set a variety of key parameters. Use the three-dimensional analysis model to analyze and obtain the hydrogen concentration in each area of the containment.

[0043] Among them, it includes real-time simulation and super-real-time simulation. Real-time simulation is a synchronous concept, an analysis consistent with the physical scene time. For example, 1000 s after the accident occurs, the simulation calculation time is also 1000 s. And super-real-time simulation is a prediction of the hydrogen risk after a certain future time. For example, 1000 s after the accident occurs, and the simulation gives the results for the next 5000 s. By displaying the three-dimensional hydrogen simulation results on the screen, it has a very intuitive effect, giving the hydrogen risk levels in different compartments and supporting accident management and emergency decision-making.

[0044] According to the internationally common judgment criteria, determine the risk level at which it is located under this hydrogen concentration. Internationally, the Shapiro diagram, σ criterion, and λ criterion are usually used to judge the flame acceleration and the occurrence of DDT during hydrogen combustion. The σ criterion and λ criterion have been applied to the numerical simulation of the three-dimensional containment as the judgment basis for hydrogen risk.

[0045] After obtaining the accident process results, use three-dimensional calculation. The advantage of this method compared with two-dimensional simulation is that it can give the hydrogen concentration in different areas of each compartment of the containment, and the analysis results are more accurate.

[0046] Adopt the real-time simulation method, which is consistent with the actual state of the power plant and can give the three-dimensional hydrogen risk inside the current containment of the power plant. At the same time, super-real-time simulation can also be adopted. By assuming an accident, predict the potential hydrogen risk, which is convenient for taking the best accident prevention and management strategies in advance.

[0047] Use the simulation results given by the method of the present disclosure, as well as the hydrogen concentration in each compartment of the containment, and according to the internationally common judgment criteria, evaluate the possible risks such as hydrogen explosion. For the areas with risks, reasonable and feasible measures can be formulated to intervene and handle the hydrogen risk in the relevant areas. In addition, according to the simulation results, it can also support the emergency decision-making of the power plant.

[0048] Embodiment 2

[0049] In one embodiment of the present disclosure, a hydrogen risk simulation system inside a containment during a severe reactor accident is provided, including:

[0050] A parameter acquisition module, configured to identify initiating events and set severe accident sequences based on typical operating conditions;

[0051] For a severe accident sequence, obtain severe reactor accident data, conduct an analysis of the severe accident process, and obtain the hydrogen source term parameters required for three-dimensional analysis;

[0052] A three-dimensional model construction module, configured to use the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set key node parameters, perform modeling and mesh generation on the nodes, and divide the containment into multiple compartment areas;

[0053] A hydrogen concentration calculation module, configured to adopt super-real-time simulation and assume the occurrence of a severe accident, use the three-dimensional analysis model to analyze the hydrogen concentration in each compartment area of the containment, determine the risk level of each area at this hydrogen concentration according to the judgment criteria, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the nuclear power plant containment.

[0054] Embodiment 3

[0055] In one embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the described method for simulating hydrogen risk inside a containment during a severe reactor accident is implemented.

[0056] Embodiment 4

[0057] An electronic device includes: a processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory so that the electronic device implements the described method for simulating hydrogen risk inside a containment during a severe reactor accident.

[0058] The present disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate for implementing in the process Figure 1 one process or multiple processes and / or blocks Figure 1means for the functions specified in one or more boxes.

[0059] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing in the process Figure 1 one process or more processes and / or boxes Figure 1 steps for the functions specified in one box or more boxes.

[0060] Although the specific embodiments of the present disclosure have been described above in conjunction with the accompanying drawings, they are not limitations on the protection scope of the present disclosure. Those skilled in the art should understand that, based on the technical solutions of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present disclosure.

Claims

1. A method for simulating the hydrogen risk inside the containment vessel during a severe reactor accident, characterized in that It includes: Based on typical operating conditions, identify the initiating event and set the severe accident sequence; For the severe accident sequence, obtain the severe accident data of the reactor, conduct a severe accident process analysis, and obtain the hydrogen production source term parameters required for three-dimensional analysis; Take the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set the key parameters of the nodes, model and mesh the nodes, and divide the containment into multiple compartment areas; The process of establishing a three-dimensional analysis model according to the actual spatial dimensions of the containment, setting the key parameters of the nodes, modeling and meshing the nodes, and dividing the containment into multiple compartment areas includes: Based on the division of the containment compartment volume, each compartment is divided into multiple nodes according to the volume size; Adopt super-real-time simulation and assume the occurrence of a severe accident. Using the three-dimensional analysis model, analyze the hydrogen concentration in each compartment area of the containment, determine the risk level of each area at this hydrogen concentration according to the judgment criteria, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the nuclear power plant containment; The method of using the three-dimensional analysis model to calculate the hydrogen concentration in each compartment area of the containment by adopting super-real-time simulation and assuming the occurrence of a severe accident is: For the prediction of hydrogen risk after a certain period of time in the future, obtain the results for the subsequent 5000 s after 1000 s after the accident occurs. By displaying the three-dimensional hydrogen simulation results on the screen, use the three-dimensional calculation program to obtain the hydrogen concentration in each compartment area of the containment.

2. The method for simulating the hydrogen risk in the containment under a severe accident of a reactor according to claim 1, wherein The hydrogen production source term parameters required for three-dimensional analysis obtained include: the mass-energy release of water and steam and the hydrogen production rate.

3. The method for simulating the hydrogen risk in the containment under a severe accident of a reactor according to claim 1, wherein The process of obtaining the process of the accident sequence and obtaining the hydrogen production source term parameters under the accident in real time is: carry out an accident process analysis through the severe accident data acquisition and analysis software to obtain the source term parameters required for three-dimensional analysis, obtain the process of the accident sequence, and obtain the hydrogen production situation under the accident in real time, including the mass-energy release of water and water vapor, etc., and the hydrogen production rate.

4. A method for simulating the hydrogen risk inside the containment during a severe accident of a reactor according to claim 1, characterized in that, The process of determining the risk level of each area at this hydrogen concentration according to the judgment criteria is: use the Shapiro diagram, σ criterion, and λ criterion to judge the flame acceleration and the occurrence of DDT during hydrogen combustion; the σ criterion and λ criterion are applied to the numerical simulation of the three-dimensional containment as the judgment basis for hydrogen risk.

5. The simulation method for hydrogen risk in the containment under a severe reactor accident according to claim 1, characterized in that, Adopt super-real-time simulation to predict the hydrogen risk after a certain period of time in the future, and display the three-dimensional hydrogen simulation results on the screen, display the hydrogen concentration in different compartment areas, and predict the hydrogen risk level of the compartments in this area.

6. A hydrogen risk simulation system in a containment under a severe reactor accident, characterized in that, It includes: A parameter acquisition module, which is used to identify the initiating event and set the severe accident sequence based on typical operating conditions; For the severe accident sequence, obtain the severe accident data of the reactor, conduct a severe accident process analysis, and obtain the hydrogen production source term parameters required for three-dimensional analysis; A three-dimensional model construction module, which is used to take the containment as the hydrogen analysis area, establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set the key parameters of the nodes, model and mesh the nodes, and divide the containment into multiple compartment areas; Establish a three-dimensional analysis model according to the actual spatial dimensions of the containment, set the key parameters of the nodes, model and mesh the nodes. The process of dividing the containment into multiple compartment areas includes: Based on the division of the containment compartment volume, each compartment is divided into multiple nodes according to the volume size; A hydrogen concentration calculation module, which is used to adopt super-real-time simulation and assume a severe accident occurs. Using the three-dimensional analysis model, analyze the hydrogen concentration in each compartment area of the containment, determine the risk level of each area at this hydrogen concentration according to the judgment criteria, and display it in real time on the three-dimensional simulation screen to predict the hydrogen risk inside the containment of the nuclear power plant; The method of using super-real-time simulation and assuming a severe accident occurs to calculate the hydrogen concentration in each compartment area of the containment by using the three-dimensional analysis model is as follows: For the prediction of hydrogen risk after a certain period of time in the future, 1000 s after the accident occurs, obtain the results for the subsequent 5000 s. By displaying the three-dimensional hydrogen simulation results on the screen, use the three-dimensional calculation program to obtain the hydrogen concentration in each compartment area of the containment.

7. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, a method for simulating hydrogen risk inside a containment during a severe accident of a reactor as described in any one of claims 1-5 is implemented.

8. An electronic device, characterized in that, Including: A processor, a memory, and a computer program; wherein, the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device runs, the processor executes the computer program stored in the memory, so that the electronic device executes a method for simulating hydrogen risk inside a containment during a severe accident of a reactor as described in any one of claims 1-5.

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