Since silicon and granite and most other crust materials melt well below 2,500 C, why doesn't the corium melt everything straight down to the Earth's mantle?
From what I understand, it’s sitting on a bed of graphite which doesn’t melt but rather sublimates to a gas at around 3,450 C. Also, they’re running a heat exchanger directly below it, draining the heat off of the supporting materials. Also I suspect that’s the temperature in the core of the Elephant’s Foot corium, not at the outer surface of it.