Core Concrete Interaction

Thermodynamic evaluation of the solidification phase of molten core–concrete under estimated Fukushima Daiichi nuclear power plant accident conditions

“…The molten pool-concrete interface would be kept at a temperature in the vicinity of the concrete liquidus and solidus temperatures. In this region of the MCCI test products, a few millimeters of a corium-rich zone and a concrete-rich zone were confirmed to be formed by convection in the molten pool [25,32]. In the case of VB-U4 products, the average composition of (U,Zr)O 2 in the concrete-rich zone is around 40 wt%, and that in the corium-rich zone is 60-66 wt% [32].…”

“…In this region of the MCCI test products, a few millimeters of a corium-rich zone and a concrete-rich zone were confirmed to be formed by convection in the molten pool [25,32]. In the case of VB-U4 products, the average composition of (U,Zr)O 2 in the concrete-rich zone is around 40 wt%, and that in the corium-rich zone is 60-66 wt% [32]. If similar phenomena occurred in the 1F MCCI, then both zones would be included in the concrete-rich region in Figure 5.…”

Experimental contribution to the corium thermodynamic modelling – The U–Zr–Al–Ca–Si–O system

“…In the case of loss of the mechanical strength of the reactor steel vessel, the molten corium may reach the concrete (Al 2 O 3 -CaO-SiO 2 ) in the cavity underneath the vessel: in this scenario the more complex U-Zr-Fe-Ca-Si-Al-O system is concerned. Many phenomena take place during Molten Corium Concrete Interaction MCCI (Journeau and Piluso, 2012): high temperature concrete decomposition, heat transfer due to gas bubbles agitation, formation of several phases, oxidation of metals, etc. Several studies on the interaction between corium and concrete were published starting from the 1980s; in particular, numerous large-scale experiments were performed on this subject.…”

Contributions of the Vulcano Experimental Programme to the Understanding of McCi Phenomena

“…Figure 6) that there is solutal convection inside the corium pool with plumes of concrete-rich and concrete-poor liquids, which are seen with a very thin spatial separation. Solutal convection is currently not considered in MCCI models [5]. All the tests (both in CCI and VULCANO) start with a transient in which hot corium is put into contact with cold concrete, leading to a rapid crust formation.…”

“…These issues have thus been classified with a high priority by the SARNET Severe Accident Research Priorities Group [4]. A recent review on state of the art MCCI can be found in Reference [5].…”