Fluid Dynamic Analysis on Hydrogen Deflagration in Vertical Flow Channel With Annular Obstacles

2017 ◽  
Author(s):  
Toshinori Matsumoto ◽  
Masatoshi Sato ◽  
Tomoyuki Sugiyama ◽  
Yu Maruyama
Keyword(s):  
Flame Propagation ◽  
Nuclear Power ◽  
Fluid Dynamic ◽  
Vertical Channel ◽  
Equation Model ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Computational Techniques ◽  
Wall Functions ◽  
Flame Acceleration

Hydrogen combustion including deflagration and detonation could become a significant threat to the integrity of containment vessel or reactor building in a severe accident of nuclear power stations. In the present study, numerical analyses were carried out for the ENACCEF No.153 test to develop computational techniques to evaluate the flame acceleration phenomenon during the hydrogen deflagration. This experiment investigated flame propagation in the hydrogen-air premixed gas in a vertical channel with flow obstacles. The reactingFoam solver of the open source CFD code, OpenFOAM, was used for the present analysis. Nineteen elementary chemical reactions were considered for the overall process of the hydrogen combustion. For a turbulent flow, renormalization group (RNG) k-ε two-equation model was used in combination with wall functions. Three manners of nodalization were applied and its influences on the flame propagation acceleration were discussed.

Simulation of ENACCEF2 Premixed Hydrogen-Air Mixture Deflagration Experiment Using OpenFOAM

2020 ◽  
Author(s):  
Justina Jaseliūnaitė ◽  
Mantas Povilaitis
Keyword(s):  
Nuclear Power ◽  
Turbulent Flame ◽  
Front Propagation ◽  
Combustible Mixture ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Variable Model ◽  
Flame Acceleration ◽  
Combustion Simulation ◽  
Acceleration Tube

Abstract During a severe accident in a nuclear power plant, hydrogen would be generated due to the oxidation of metallic components in steam atmosphere. In the containment hydrogen would form a combustible mixture, posing a deflagration or even detonation risk threatening the integrity of the containment. In order to estimate possible loads generated by the hydrogen combustion, reliable numerical tools are needed to simulate the deflagration process. Recently, the French MITHYGENE project consortium and the European Technical Safety Organization Network (ETSON) organized a benchmark on hydrogen combustion to identify the current level of the computational tools in the area of hydrogen combustion simulation under a severe accident typical conditions. The benchmark was based on the experiments performed in the ENACCEF2 facility. This paper presents post-benchmark simulations of the selected ENACCEF2 facility premixed hydrogen combustion experiment. The presented simulations were performed using a custom-built turbulent combustion OpenFOAM solver based on the progress variable model. Turbulent flame acceleration phase in the acceleration tube was well predicted. Furthermore, the simulations were able to capture the interaction between the flame and shock wave which was generated by the turbulent deflagration flame and reflected at the end of the ENACCEF2 tube. The overall numerical results show good agreement with the qualitative and quantitative behavior of the velocity results and flame front propagation.

scholarly journals Numerical Analysis for Hydrogen Flame Acceleration during a Severe Accident Initiated by SBLOCA in the APR1400 Containment

Hydrogen ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 28-42
Author(s):  
Hyung-Seok Kang ◽  
Jongtae Kim ◽  
Seong-Wan Hong
Keyword(s):  
Nuclear Power ◽  
Peak Pressure ◽  
Power Reactor ◽  
Hydrogen Combustion ◽  
Hydrogen Release ◽  
Severe Accident ◽  
Hydrogen Distribution ◽  
Nuclear Power Reactor ◽  
Flame Acceleration ◽  
Fracture Pressure

We performed a hydrogen combustion analysis in the Advanced Power Reactor 1400 MWe (APR1400) containment during a severe accident initiated by a small break loss of coolant accident (SBLOCA) which occurred at a lower part of the cold leg using a multi-dimensional hydrogen analysis system (MHAS) to confirm the integrity of the APR1400 containment. The MHAS was developed by combining MAAP, GASFLOW, and COM3D to simulate hydrogen release, distribution and combustion in the containment of a nuclear power plant during the severe accidents in the containment of a nuclear power reactor. The calculated peak pressure due to the flame acceleration by the COM3D, using the GASFLOW results as an initial condition of the hydrogen distribution, was approximately 555 kPa, which is lower than the fracture pressure 1223 kPa of the APR1400 containment. To induce a higher peak pressure resulted from a strong flame acceleration in the containment, we intentionally assumed several things in developing an accident scenario of the SBLOCA. Therefore, we may judge that the integrity of the APR1400 containment can be maintained even though the hydrogen combustion occurs during the severe accident initiated by the SBLOCA.

scholarly journals Numerical Analysis for Hydrogen Flame Acceleration during a Severe Accident in the APR1400 Containment Using a Multi-Dimensional Hydrogen Analysis System

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6151
Author(s):  
Hyung Seok Kang ◽  
Jongtae Kim ◽  
Seong Wan Hong ◽  
Sang Baik Kim
Keyword(s):  
Turbulent Flame ◽  
Hydrogen Combustion ◽  
Hydrogen Release ◽  
Severe Accident ◽  
Flame Acceleration ◽  
Turbulent Flame Speed ◽  
Analysis Methodology ◽  
Hydrogen Flame ◽  
Hydrogen Analysis ◽  
Analysis System

Korea Atomic Energy Research Institute (KAERI) established a multi-dimensional hydrogen analysis system to evaluate hydrogen release, distribution, and combustion in the containment of a Nuclear Power Plant (NPP), using MAAP, GASFLOW, and COM3D. In particular, KAERI developed an analysis methodology for a hydrogen flame acceleration, on the basis of the COM3D validation results against measured data of the hydrogen combustion tests in the ENACCEF and THAI facilities. The proposed analysis methodology accurately predicted the peak overpressure with an error range of approximately ±10%, using the Kawanabe model used for a turbulent flame speed in the COM3D. KAERI performed a hydrogen flame acceleration analysis using the multi-dimensional hydrogen analysis system for a severe accident initiated by a station blackout (SBO), under the assumption of 100% metal–water reaction in the Reactor Pressure Vessel (RPV), to evaluate an overpressure buildup in the containment of the Advanced Power Reactor 1400 MWe (APR1400). The magnitude of the overpressure buildup in the APR1400 containment might be used as a criterion to judge whether the containment integrity is maintained or not, when the hydrogen combustion occurs during a severe accident. The COM3D calculation results using the established analysis methodology showed that the calculated peak pressure in the containment was lower than the fracture pressure of the APR1400 containment. This calculation result might have resulted from a large air volume of the containment, a reduced hydrogen concentration owing to passive auto-catalytic recombiners installed in the containment during the hydrogen release from the RPV, and a lot of stem presence during the hydrogen combustion period in the containment. Therefore, we found that the current design of the APR1400 containment maintained its integrity when the flame acceleration occurred during the severe accident initiated by the SBO accident.

Numerical Simulation of Hydrogen Dispersion Inside a Compartment Using HYDRAGON Code

2016 ◽  
Author(s):  
M. Saeed ◽  
Yu Jiyang ◽  
B. X. Hou ◽  
Aniseh A. A. Abdalla ◽  
Zhang Chunhui
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Concentration Distribution ◽  
Nuclear Power ◽  
Turbulence Models ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Normal Operation ◽  
Accurate Estimation ◽  
Nuclear Power Plant Accident

During severe accident in the nuclear power plant, a considerable amount of hydrogen can be generated by an active reaction of the fuel-cladding with steam within the pressure vessel which may be released into the containment of nuclear power plant. Hydrogen combustion may occur where there is sufficient oxygen, and the hydrogen release rates exceed 10% of the containment. During hydrogen combustion, detonation force and short term pressure may be produced. The production of these gas species can be detrimental to the structural integrity of the safety systems of the reactor and the containment. In 1979, the Three Mile Island (1979) accident occurred. This accident compelled experts and researchers to focus on the study of distribution of hydrogen inside the containment of nuclear power plant. However after the Fukushima Dai-ichi nuclear power plant accident (2011), the modeling of the gas behavior became important topic for scientists. For the stable and normal operation of the containment, it is essential to understand the behavior of hydrogen inside the containment of nuclear power plant in order to mitigate the occurrence of these types of accidents in the future. For this purpose, it is important to identify how burnable hydrogen clouds are produced in the containment of nuclear power plant. The combustion of hydrogen may occur in different modes based on geometrical complexity and gas composition. Reliable turbulence models must be used in order to obtain an accurate estimation of the concentration distribution as a function of time and other physical phenomena of the gas mixture. In this study, a small scale hydrogen-dispersion case is selected as a benchmark to address turbulence models. The computations are performed using HYDRAGON code developed by Department of Engineering Physics, Tsinghua University, China. HYDRAGON code is a three dimensional thermal-hydraulics analysis code. The purpose of this code is to predict the behavior of hydrogen gas and multiple gas species inside the containment of nuclear power plant during severe accident. This code mainly adopts CFD models and structural correlations used for wall flow resistance instead of using boundary layer at a wall. HYDROGAN code analyzes many processes such as hydrogen diffusion condensation, combustion, gas stratification, evaporation, mixing process. The main purpose of this research is to study the influence of turbulence models to the concentration distribution and to demonstrate the code thermal-hydraulic simulation capability during nuclear power plant accident. The calculated results of various turbulence models have different prediction values in different compartments. The results of k–ε turbulence model are in reasonable agreement as compared to the benchmark experimental data.

Analysis of RCS Depressurization Effects on Containment Temperature for Qinshan Phase II Nuclear Power Plant

2014 ◽  
Author(s):  
Liu Lili ◽  
Zhang Ming ◽  
Deng Jian
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Hydrogen Generation ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Generation Rate ◽  
Pressurized Water Reactor ◽  
Gas Temperature ◽  
Pressurized Water

A severe accident code was applied for modeling of a typical pressurized water reactor (PWR) nuclear power plant, and the effects of RCS depressurization on the gas temperature of the relief tank cell in the containment during a station blackout (SBO) induced accident was analyzed. The sensitivity calculation indicated that the hydrogen generation rate obviously increased due to RCS depressurization in a critical stage. The results show that RCS depressurization can play an important role in hydrogen generation rate and total accumulation, and the temperature of the containment atmosphere is highly influenced by hydrogen combustion. High temperature induced by hydrogen combustion may degrade the equipment and instruments capabilities. Based on this analysis, a feasible strategy of RCS depressurization for mitigating the accident consequence is provided for developing the capacity of the SBO treatment of Qinshan Phase Nuclear Power Plant (QSP-II NPP).

Effect on Hydrogen Risk of Initial Gas Injection Time During AP1000 Post-Inerting

2016 ◽  
Author(s):  
XueFeng Lyu ◽  
YanLin Chen ◽  
XiaoBo Li ◽  
ShengFei Wang ◽  
Yu Yu ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Hydrogen Diffusion ◽  
Gas Injection ◽  
Inert Gas ◽  
Severe Accident ◽  
Injection Time ◽  
Steam Generation ◽  
Flame Acceleration ◽  
Average Temperature ◽  
Total Elimination

To calculate the hydrogen risk at severe accident of small break of cold leg in 1# steam generation compartment with ADS4 invalid in AP1000 nuclear power plant, and apply the results to level2 probabilistic safety analysis, we study the effect of initial gas injection time on reducing hydrogen risk during AP1000 post-inerting, the initial gas injection times are 300 second, 500second, 700second, respectively. First, analyzing the total elimination of hydrogen by recombiners. Then, analyzing the average hydrogen mole fraction, flame acceleration factor in 1# steam generation compartment and in upper space of containment. Finally, analyzing the pressure and average temperature in containment. The results show that, the premature injection of inert gas can slow down hydrogen diffusion rate from 1# steam generation compartment to the upper space of containment, which causes hydrogen risk rising in 1# steam generation compartment. Post-inerting can ease hydrogen risk in upper space of containment, but can’t ease hydrogen risk in 1# steam generation compartment effectively. The pressure of containment is only relevant to the total mass of inert gas, and the pressure of containment is always less than limit pressure, so the containment breakage is nearly impossible.

Development and Validation of the Parallel All-Speed CFD Code GASFLOW-MPI for Detonation of Premixed H2-Air Mixture in a Hemispherical Balloon

2017 ◽  
Author(s):  
Jianjun Xiao ◽  
Wolfgang Breitung ◽  
Mike Kuznetsov ◽  
Jack Travis ◽  
Reinhard Redlinger
Keyword(s):  
Nuclear Power ◽  
Nuclear Reactor ◽  
Turbulent Dispersion ◽  
Severe Accident ◽  
Flame Acceleration ◽  
Model Predictions ◽  
Computational Fluid Dynamics Cfd ◽  
Detonation Transition ◽  
Reliability And Robustness ◽  
Development And Validation

The objective was to develop a validated computational fluid dynamics (CFD) based approach for predicting hydrogen detonations and the mechanical loads. Applications of interest were scenarios relevant to hydrogen explosion risk assessment in nuclear power plant under hypothetical severe accident. Model developments were conducted within the framework of the parallel scientific computational tool GASFLOW-MPI thanks to its effectiveness, reliability and robustness in predicting all-speed flows. Validation was completed for hydrogen detonation phenomena in 3-D hemispherical hydrogen cloud. Excellent comparisons between experimental data and model predictions were observed. With the developed detonation modeling capability, the all-speed CFD code GASFLOW-MPI can be applied to model both turbulent dispersion and hydrogen detonation phenomena that occurred in the nuclear reactor containment during severe accident. Further model developments and validations will be performed for flame acceleration (FA) and deflagration to detonation transition (DDT).

scholarly journals Numerical Analysis for Hydrogen Flame Acceleration during a Severe Accident in the APR1400 Containment Using a Multi-Dimensional Hydrogen Analysis System

2020 ◽  
Author(s):  
Hyung Seok Kang ◽  
Jongtae Kim ◽  
Seong Wan Hong ◽  
Sang Baik Kim
Keyword(s):  
Nuclear Power ◽  
Turbulent Flame ◽  
Hydrogen Release ◽  
Severe Accident ◽  
Flame Acceleration ◽  
Turbulent Flame Speed ◽  
Analysis Methodology ◽  
Hydrogen Flame ◽  
Hydrogen Analysis ◽  
Analysis System

Korea Atomic Energy Research Institute (KAERI) established a multi-dimensional hydrogen analysis system to evaluate a hydrogen release, distribution, and combustion in the containment of a nuclear power plant using MAAP, GASFLOW, and COM3D. KAERI developed the COM3D analysis methodology on the basis of the COM3D validation results against the experiments of ENACCEF and THAI. The proposed analysis methodology accurately predicts the peak overpressure with an error range of approximately ±10% using the Kawanabe turbulent flame speed model. KAERI performed a hydrogen flame acceleration analysis using the multi-dimensional hydrogen analysis system for a severe accident initiated by a station blackout (SBO) under the assumption of 100% metal-water reaction in the reactor pressure vessel for evaluating an overpressure buildup in the Advanced Power Reactor 1400 MWe (APR1400). The COM3D calculation results using the established analysis methodology showed that the calculated peak pressure in the containment was much lower than the fracture pressure of the APR1400 containment. This calculation result may have resulted from a large air volume of the containment, a reduced hydrogen concentration owing to passive auto-catalytic recombiners installed in the containment, and a lot of stem presence during the hydrogen flame acceleration in the containment. Therefore, we can know that the current design of the APR1400 containment maintains its integrity when the flame acceleration occurs during the severe accident initiated by the SBO accident.

Upward Flame Propagation Experiments on Hydrogen Combustion in a 220 cub. m Vessel

2014 ◽  
Author(s):  
Mike Kuznetsov ◽  
Gerold Stern ◽  
Ivo Kljenak ◽  
Marko Matkovič ◽  
Borut Mavko
Keyword(s):  
Flame Propagation ◽  
High Speed ◽  
Initial Pressure ◽  
Hydrogen Combustion ◽  
Severe Accident ◽  
Numerical Code ◽  
Internal Diameter ◽  
Flame Velocity ◽  
Experimental Facility ◽  
Pressurized Water

During a hypothetical severe accident in a pressurized water reactor (PWR) of nuclear power plant, hydrogen would be generated during the degradation of the reactor core. The ignition and ensuing combustion of hydrogen could cause a sharp pressure increase, which could threaten the integrity of the containment. The present work describes the execution and results of the Upward Flame Propagation Experiment (UFPE) on hydrogen combustion within the EC LACOMECO project. Two experiments were performed at the HYKA A2 experimental facility (KIT), which is a cylindrical vessel of 220 m3 free volume, 9.1 m height and 6.0 m internal diameter. A homogeneous mixture of hydrogen (11–12 vol.%), steam (20–21 vol.%) and air was established in the vessel. The initial pressure was 1.5 bar, and the average initial temperature was about 90.0 °C. The mixture was ignited at the bottom of the vessel and the ensuing axial and radial flame propagation were observed. Pressure, temperature and flame velocity were measured at different axial and radial locations. The flame propagation was recorded by a high speed video combined with a Background Oriented Schlieren (BOS) method. The experimental results were finally compared to the results of the well-known THAI HD-22 experiment, which was performed at almost similar conditions. The objective of current work was to investigate the effect of scale on flame propagation regime in order to clarify how can phenomena observed in a scaled-down experimental facility be extrapolated to an actual containment scale. Another goal was to provide detailed experimental data for numerical code validations in a large scale.

A Study on Quenching Meshes as a Possible Controlling Tool of Hydrogen Explosion in Nuclear Power Plants

2002 ◽  
Author(s):  
Hong Jip Kim ◽  
Seong Wan Hong ◽  
Hee Dong Kim ◽  
Seung Yeon Yang ◽  
Suk Ho Chung
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Initial Pressure ◽  
Phenomenological Analysis ◽  
Hydrogen Combustion ◽  
Severe Accident

Characteristics of quenching meshes for control of hydrogen combustion in severe accident in nuclear power plant are experimentally investigated. Quenching distances of hydrogen-air mixtures without steam over a range of initial pressure are measured. Those of stoichiometric hydrogen-air mixtures with steam with respect to initial pressure are also measured. In addition, parameters that should be considered to ensure the performance and validity of the installation of quenching meshes for the control of hydrogen combustion in closed compartments are obtained from a simplified phenomenological analysis and experimentally investigated.

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