VULCANO VB-U7 experiment on interaction between oxidic corium and hematite-containing concrete

In a severe accident, the core of a reactor melts and forms corium, a mixture that includes molten UO₂ and ZrO₂. If the reactor pressure vessel fails, corium can interact with concrete.

This paper describes the VB-U7 experiment, which was performed in the VULCANO facility in Cadarache, France, in co-operation between CEA and VTT. This test aims at studying the interaction of more than 50 kg of prototypic oxidic corium with EPR sacrificial ferro-siliceous concrete. The experimental configuration, the measured data and post examination and analysis results are presented.

This test showed that EPR-type ferro-siliceous sacrificial concrete was anisotropically ablated by oxidic corium. This behavior is similar to that of other silica-rich concretes previously tested in CCI and VULCANO facilities. The corium temperature decreased to the value corresponding to about 50 vol% solid fraction when the concrete test section broke, leading to significant spreading.