Investigation of the premixing phase of a steam explosion with hot spheres

The multiphase, transient and three-dimensional interaction of molten corium with water during the premixing phase of a steam explosion has been simulated in the QUEOS facility using a large number of small solid spheres at temperatures up to 2200 degrees C. The objective of the experiments is to establish a data base for testing the models of heat and momentum transfer in multi-fluid codes as well as the codes' capability to correctly describe multi-phase flows. The paper reports on three experiments with up to 10 kg of spheres made of molybdenum. Results from calculations with the IVA-KA code are compared with experimental data. The agreement obtained is remarkable and the calculations show that the intense multiphase interactions obtained in QUEOS constitute very critical and thus valuable test cases. 21 refs., 18 figs., 2 tabs