The Elephant's Foot
The Elephant’s Foot is an extremely radioactive mass of corium formed during the Chernobyl disaster in April 1986, and was discovered in December 1986. It is named for its wrinkly appearance, resembling the foot of an elephant. The corium mass is beneath Reactor N. 4 of the Chernobyl Nuclear Power Plant, in under-reactor room 217.
The Elephant's Foot is a large mass of black LFCM with many layers, externally resembling tree bark and glass. The mass is quite dense, unyielding to a drill but able to be damaged by a Kalashnikov rifle. By June 1998, the outer layers of the mass began to turn to dust and the entire mass was starting to crack. The mass has penetrated through at least 2 m (6 ft 7 in) of concrete.
It is composed chiefly of silicon dioxide, with traces of uranium. The mass is largely homogeneous, though the depolymerized silicate glass contains occasional crystalline grains of zircon. These grains of zircon are not elongated, suggesting a moderate crystallization rate. While uranium dioxide dendrites grew quickly at high temperatures within the lava, the zircon began crystallization during slow cooling of the lava. Despite the distribution of uranium bearing particles not being uniform, the radioactivity of the mass is evenly distributed.
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