The possibility to adequately simulate the flow circulation in the atmosphere of a nuclear power plant containment at accident conditions using a lumped-parameter code is investigated. An experiment on containment atmosphere mixing and stratification, which was performed in the TOSQAN experimental facility at IRSN in Saclay (France), was considered. During some phases of the experiment, steady states were achieved by keeping the boundary conditions constant. Two steady states during which natural convection was the dominant gas flow mechanism were simulated independently with the CFD code CFX4, whereas the entire transient was simulated with the lumped-parameter code ASTEC. The nodalisation of the lumped-parameter model was based on the flow pattern during the considered steady states, simulated with the CFD code. The lumped-parameter simulation succeeded in replicating the basic pattern of natural circulation in the vessel atmosphere during the two considered steady states, determined with the CFD code.

This content is only available via PDF.
You do not currently have access to this content.