The corium melt then accumulate at the bottom of the reactor vessel. They look like whitish yellow patches on the surface of the solidified corium. The calcium oxide, silica, and silicates melt and are mixed into the corium. The corium flowed from the reactor in three streams. Most cases will show a wedge-shaped connective tissue necrosis in the deep corium. Several reactions occur between the concrete and the corium melt. The largest known amounts of corium were formed during the Chernobyl disaster. It was therefore necessary to drain the bubbler pool before the corium reached it. The layer of solidified corium ranged in thickness from 5 to 45 cm. An accumulated mass of corium will lose less heat than a thinly spread layer. It is generally more pigmented than the surrounding corium. This mode of corium ejection may lead to direct containment heating (DCH). During the interaction between corium and concrete, very high temperatures can be achieved. Corium of sufficient temperature can melt concrete. The corium was formed in three phases.