A review on hydrogen generation, explosion, and mitigation during severe accidents in light water nuclear reactors

Simulation of hydrogen distribution in an Indian Nuclear Reactor Containment

Large eddy simulation of turbulent flow using the parallel computational fluid dynamics code GASFLOW-MPI

Simulation of gas mixing and transport in a multi-compartment geometry using the GOTHIC containment code and relatively coarse meshes

Three-dimensional all-speed CFD code for safety analysis of nuclear reactor containment: Status of GASFLOW parallelization, model development, validation and application

CFD evaluation of hydrogen risk mitigation measures in a VVER-440/213 containment

OECD/NEA Sandia Fuel Project phase I: Benchmark of the ignition testing

Hydrogen combustion may represent a threat to containment integrity in a VVER-440/213 plant owing to the combination of high pressure and high temperature. A study has been carried out using the GASFLOW 2.1 three-dimensional CFD code to evaluate the hydrogen distribution in the containment during a beyond design basis accident. The VVER-440/213 containment input model consists of two 3D blocks connected via one-dimensional (1D) ducts. One 3D block contains the reactor building and the accident localization tower with the suppression pools. Another 3D block models the air traps. 1D ducts represent the check valves connecting the accident localization tower with the air traps. The VVER pressure suppression system, called “bubbler condenser,” was modeled as a distributed heat sink with water thermodynamic properties. This model accounts for the energy balance. However, it is not currently possible to model dynamic phenomena associated with the water pools (e.g., vent clearing, level change). The GASFLOW 2.1 calculation gave detailed results for the spatial distribution of thermal-hydraulic parameters and gas concentrations. The range and trend of the parameters are reasonable and valuable. There are particularly interesting circulation patterns around the steam generators, in the bubbler tower and other primary system compartments. In case of the bubbler tower, concentration and temperature contour plots show an inhomogeneous distribution along the height and width, changing during the accident. Hydrogen concentrations also vary within primary system compartments displaying lower as well as higher (up to 13–20% and higher) values in some nodes. Prediction of such concentration distributions was not previously possible with lumped parameter codes. GASFLOW 2.1 calculations were compared with CONTAIN 1.2 (lumped parameter code) results. Apart from the qualitatively similar trends, there are, for the time being, quantitative differences between the results concerning, for example, pressure histories, or the total amount of steam available in the containment. The results confirm the importance of detailed modeling of the containment, as well as of the bubbler condenser and sump water pools. The study showed that modeling of hydrogen distribution in the VVER-440/213 containment was possible using the GASFLOW 2.1 code with reasonable results and remarkable physical insights.Copyright © 2002 by ASME

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Hydrogen Mixing Analyses for a VVER Containment

Accident loads for a VVER-440/213 containment

Severe accident simulation using CFD codes

Zsolt Téchy

Papers

CFD evaluation of hydrogen risk mitigation measures in a VVER-440/213 containment

OECD/NEA Sandia Fuel Project phase I: Benchmark of the ignition testing

Hydrogen Mixing Analyses for a VVER Containment

Accident loads for a VVER-440/213 containment

Severe accident simulation using CFD codes