Corium (nuclear reactor) from the pre-meltdown reactor or be due to spontaneous fission of reactor-created actinides. In the absence of adequate cooling, the materials inside of the reactor vessel overheat and deform as they undergo thermal expansion, and the reactor structure fails once the temperature reaches the melting point of its structural materials. The corium melt then accumulates at the bottom of the reactor vessel. In the case of adequate cooling of the corium melt, the melt can solidify and the spread of damage is limited to the reactor itself. However, corium may melt through the reactor vessel and flow out or be
Loss-of-coolant accident order to mitigate the result of the event: Loss-of-coolant accident A loss-of-coolant accident (LOCA) is a mode of failure for a nuclear reactor; if not managed effectively, the results of a LOCA could result in reactor core damage. Each nuclear plant's emergency core cooling system (ECCS) exists specifically to deal with a LOCA. Nuclear reactors generate heat internally; to remove this heat and convert it into useful electrical power, a coolant system is used. If this coolant flow is reduced, or lost altogether, the nuclear reactor's emergency shutdown system is designed to stop the fission chain reaction. However, due to