Atomic Energy Society of Japan

In Fukushima Daiichi Nuclear Power Station accident, the formation of “metal-rich pool” in the lower plenum during the late phase of core degradation has been considered to have taken place, which could have triggered the failure of reactor pressure vessel. In this study, the formation mechanism of “metal-rich debris”, which could be a source of the metal-rich pool, was investigated by an experiment of non-isothermal reaction between molten Fe-Zr material and stainless steel (SS) at lower temperatures. We will present the results that the reaction products formed on the Fe-Zr/SS interface prevented the heat transfer, which could be useful knowledge for determination of the user-defined parameter of severe accident code.