Insight into steam explosions with corium melts in KROTOS Original Research Article

This paper describes two KROTOS tests in which ∼4 kg of corium melt was injected into a ∼1-m deep subcooled water pool. These tests were performed in a test vessel that allowed direct visual observations of melt injection and mixing conditions. Visual observations showed that the corium jet penetrated deep into the water while maintaining its shape. The tests did not produce spontaneous explosions. However, the second test with an external trigger produced an explosion with a relatively low efficiency of 0.15%. This is different from the behaviour of alumina melts, which exhibit one order of magnitude higher explosion efficiencies. This paper describes possible mechanisms that could have contributed to the reduced efficiency with corium melt.