VALIDATION OF THE CHYMES MIXING MODEL

This paper contains a discussion of the work being performed in the UK to validate the CHYMES coarse mixing model. Attention is focussed on the MIXA experiments performed at Winfrith Technology Centre in which 3 kg of molten fuel simulant were released into water. The validation of CHYMES against one of these experiments (MIXA06) is discussed in de tail. It is concluded that CHYMES can reproduce some features of the e xperiment (such as the existence of a steam chimney around the mixture and the steam production rate within a factor of two) but it does not predict the observed mixture development (the radial spreading and th e deceleration of the first melt arriving at the surface) well. Additi onal model development and experimental analysis underway to resolve t hese differences is discussed.