Melting behavior of concrete under severe accident conditions involving high-temperature steam atmospheres and reactions with molten core materials

Sato, Takumi; Sudo, Ayako; Nagae, Yuji; Igarashi, Go*; Miura, Taito*; Maruyama, Ippei*; Miyamoto, Shintoro*

no journal, , 

During the Fukushima Daiichi Nuclear Power Station accident, fuel debris fell into the pedestal and damaged the concrete of the pedestal section. In particular, an internal investigation of the Unit 1 pedestal revealed that the wall concrete had disappeared and the rebar was exposed. The remaining rebar suggests that the concrete failure progressed at relatively low temperatures below the melting point of iron, different from the conventional MCCI reaction. To understand the failure mechanism, we conducted small-scale elemental tests, including a melting test in a high-temperature steam atmosphere and a reaction test with fuel debris.