Coupled AC2-CFD simulations for a high-pressure core melt accident scenario
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Joachim Herb
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Hristo V. Hristov
Abstract
Even though very unlikely to occur, severe accident scenarios in nuclear power plants have to be analyzed. During high-pressure core meltdown scenarios in a pressurized water reactor the primary circuit should fail first. Previous analyses found that a free convection flow within the vertical steam generator (SG) tubes with a simultaneous stratified gas counterflow in the hot legs could arise. This phenomenon leads to higher thermal loads on individual SG tubes which might then fail leading to a containment bypass and the release of radioactive material into the environment. Lumped parameter system codes used for safety analyses do not provide the models necessary to simulate phenomena like mixing in three-dimensional flows and could not consider local turbulence effects. Computational fluid dynamic (CFD) codes provide such capabilities but are much more computationally expensive. Coupling of a system code with a CFD code can therefore be used to simulate such phenomena. The advantages of both approaches can be maximized by splitting up the simulation domain between the codes, depending on the expected flow conditions. The system code AC2 coupled with the CFD code OpenFOAM was used to simulate part of the severe accident transient. Free convection in the hot leg and the U-tubes of the vertical SG was observed in case of high-pressure severe accident sequences. The thermal load of individual SG tubes has been estimated from the results. These loads can be used as inputs for structural-mechanical analyses to estimate which part of the primary circuit would fail first.
Funding source: German Federal Ministry of the Environment, Nature Conservation, Nuclear Safety and Consumer Protection
Award Identifier / Grant number: 4719R01376
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Research ethics: Not applicable.
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Author contributions: The authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: The authors state no conflict of interest.
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Research funding: This work was funded by the German Federal Ministry of the Environment, Nature Conservation, Nuclear Safety and Consumer Protection within the project 4719R01376 “Further research on the HD core meltdown process by coupling a CFD loop model with ATHLET-CD”.
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Data availability: Not applicable.
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© 2024 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- The 34th German CFD network of competence meeting: numerical 3D simulation of reactor primary cooling circuit and containment flows
- The European GO-VIKING project on flow-induced vibrations: overview and current status
- CFD simulation on droplet behaviour in post-dryout region
- Coupled AC2-CFD simulations for a high-pressure core melt accident scenario
- Validation of coupled ATHLET-OpenFOAM simulation on a large-scale single- and two-phase flow experiment
- CFD modelling of flashing flows for nuclear safety analysis: possibilities and challenges
- Implementation of the preCICE coupling interface for AC2/ATHLET
- Large-scale PANDA facility – radiation experiments and CFD calculations
- Overview on GRS CFD activities related to containment applications
- Calendar of events
Articles in the same Issue
- Frontmatter
- The 34th German CFD network of competence meeting: numerical 3D simulation of reactor primary cooling circuit and containment flows
- The European GO-VIKING project on flow-induced vibrations: overview and current status
- CFD simulation on droplet behaviour in post-dryout region
- Coupled AC2-CFD simulations for a high-pressure core melt accident scenario
- Validation of coupled ATHLET-OpenFOAM simulation on a large-scale single- and two-phase flow experiment
- CFD modelling of flashing flows for nuclear safety analysis: possibilities and challenges
- Implementation of the preCICE coupling interface for AC2/ATHLET
- Large-scale PANDA facility – radiation experiments and CFD calculations
- Overview on GRS CFD activities related to containment applications
- Calendar of events
