[en] Although many studies have been performed worldwide on a steam explosion, there are only a few tests using real reactor materials. So the TROI steam explosion experiments have been carried out to evaluate the explosivity of corium. In the previous TROI tests, the effects of the water depth, corium composition and an external trigger were studied on the occurrence of a steam explosion in a 60 cm wide interaction vessel. It turned out that a shallow water pool, eutectic or pure material and the use of an external trigger easily led to steam explosions. However, tests with metal added corium are needed since the real core material contains iron and zirconium. In this paper, the results of two TROI tests (test No. 43 and 44) are presented using a mixture of spontaneously explosive eutectic corium (70 : 30 at weight percent of UO₂ : ZrO₂) and iron with or without applying an external trigger