
View documentNKS Programme Area:  NKSR  Research Area:  Thermo hydraulics  Report Number:  NKS249  Report Title:  Numerical modelling of pressure suppression pools with CFD and FEM codes  Activity Acronym:  POOL  Authors:  Timo Pättikangas, Jarto Niemi, Antti Timperi  Abstract:  Experiments on largebreak lossofcoolant accident for BWR is modeled with computational fluid (CFD) dynamics and finite element calculations. In the CFD calculations, the directcontact condensation in the pressure suppression pool is studied. The heat transfer in the liquid phase is modeled with the HughesDuffey correlation based on the surface renewal model. The heat transfer is proportional to the square root of the turbulence kinetic energy. The condensation models are implemented with userdefined functions in the EulerEuler twophase model of the Fluent 12.1 CFD code.
The rapid collapse of a large steam bubble and the resulting pressure source is studied analytically and numerically. Pressure source obtained from simplified calculations is used for studying the structural effects and FSI in a realistic BWR containment. The collapse results in volume acceleration, which induces pressure loads on the pool walls. In the case of a spherical bubble, the velocity term of the volume acceleration is responsible of the largest pressure load. As the amount of air in the bubble is decreased, the peak pressure increases. However, when the water compressibility is accounted for, the finite speed of sound becomes a limiting factor.  Keywords:  Condensation pool, pressure suppression pool, BWR, CFD, fluidstructure interactions, FSI  Publication date:  01 Jun 2011  ISBN:  ISBN 9788778933218  Number of downloads:  1753  Download:  NKS249.pdf 

