Corium (nuclear reactor) Corium (nuclear reactor) Corium (also called fuel containing material (FCM) or lava-like fuel containing material (LFCM)) is the lava-like mixture of fissile material created in a nuclear reactor's core during a nuclear meltdown. It consists of nuclear fuel, fission products, control rods, structural materials from the affected parts of the reactor, products of their chemical reaction with air, water and steam, and, in the event that the reactor vessel is breached, molten concrete from the floor of the reactor room. The heat causing the melting of a reactor may originate from the nuclear chain reaction, but more commonly decay heat
Very-high-temperature reactor Very-high-temperature reactor The very-high-temperature reactor (VHTR), or high-temperature gas-cooled reactor (HTGR), is a Generation IV reactor concept that uses a graphite-moderated nuclear reactor with a once-through uranium fuel cycle. The VHTR is a type of high-temperature reactor (HTR) that can conceptually have an outlet temperature of 1000 °C. The reactor core can be either a "prismatic block" or a "pebble-bed" core. The high temperatures enable applications such as process heat or hydrogen production via the thermochemical sulfur–iodine cycle. The VHTR is a type of high-temperature reactor that conceptually can reach high outlet temperatures (up to 1000 °C); however, in practice