A transient two-phase model to describe thermal detonations based on hydrodynamic fragmentation

To predict the effect of a fuel-coolant interaction after a hypothetical core melt down accident, a new transient model based on hydrodynamic fragmentation has been developed, using a two-phase description which considers relative velocities between melt and coolant. To examine the escalation behavior of thermally explosive mixtures, various calculations for Sn-H2O and corium-H2O systems have been carried out. For an example case, the results obtained by the transient and a steady-state model, also developed at the IKE, were consistent. An excellent agreement between theoretical and experimental results was obtained for a chosen Sn-H2O system (Standard Experiment No. T-107 of Fry and Robinson)