The multiphase, transient, and three-dimensional interaction of molten
corium with water during the premixing phase of a steam explosion is
simulated in the QUEOS facility using a barge number of smalt solid sp
heres at temperatures up to 2300 K. The objective of the experiments i
s to establish a database for testing the models of heat and momentum
transfer in multifluid codes as well as the codes' capability to corre
ctly describe multiphase flows. Three experiments with up to 10 kg of
spheres made of molybdenum are discussed. Results from calculations wi
th the NA-KA code are compared with experimental data. The agreement o
btained is encouraging, and the calculations show that the intense mul
tiphase interactions obtained in QUEOS constitute very critical and th
us valuable test cases.