The Elephant’s Foot is a highly radioactive formation located beneath the remnants of Reactor No. 4 at the Chernobyl Nuclear Power Plant, a direct consequence of the April 1986 nuclear accident.
Formation and Composition
The Elephant’s Foot formed from corium, a lava-like material created during the meltdown of Reactor No. 4. Corium is produced when nuclear fuel and reactor core structures overheat and melt together. This occurred as the reactor core reached temperatures exceeding 2,900 degrees Fahrenheit, causing its contents to liquefy and flow.
The molten mass, a mixture of nuclear fuel, concrete, sand, and core sealing materials, burned through several meters of reinforced concrete and flowed through pipes and fissures, solidifying in a maintenance corridor beneath the reactor. The Elephant’s Foot is primarily composed of silicon dioxide, along with smaller amounts of uranium, zirconium, iron, and other oxides, giving it a black, glassy appearance with a layered, tree bark-like texture.
Current Radiation Levels and Accessibility
When first discovered in December 1986, the Elephant’s Foot emitted radiation at approximately 8,000 to 10,000 roentgens per hour. Exposure to this level was rapidly lethal.
Over the decades, radiation intensity has significantly decreased due to radioactive decay. By 1996, it was possible for individuals, such as Artur Korneyev, to briefly approach the mass to take photographs, although protective gear was still necessary. While now more than ten times less radioactive than at its discovery, it remains lethally hazardous, estimated to emit around 200-300 roentgens per hour, which can be fatal within two hours of exposure.
Long-Term Evolution and Future Concerns
The Elephant’s Foot continues to undergo physical and chemical degradation. Its surface has cracked and degraded over time, and its consistency has shifted from a hard, unyielding mass to something resembling sand. This ongoing disintegration is partly due to the intense internal radiation destroying its physical structure.
Concerns persist regarding the long-term stability of the Elephant’s Foot and other corium formations. The potential for further dust formation raises worries about the release of radioactive particles into the environment if containment is compromised. While fears of it melting deeper into the ground and contaminating groundwater have largely proven unfounded, the material still presents a risk if its integrity is not maintained.
Containment and Monitoring Efforts
Significant engineering efforts have been undertaken to contain and monitor the Elephant’s Foot and the broader damaged reactor. The original concrete sarcophagus, built hastily after the disaster, was designed to contain the radioactive materials. This structure, however, was a temporary solution.
In 2016, the New Safe Confinement (NSC) was slid into place over the sarcophagus and Reactor No. 4. This massive arch-shaped structure, the world’s largest movable land-based structure, was designed to prevent further release of radioactive materials and allow for safer decommissioning work. Within the NSC, ongoing monitoring processes, including remote sensing and robotic inspections, assess the condition of the Elephant’s Foot and its radiation levels without direct human exposure. These efforts aim to mitigate the ongoing danger and prevent environmental contamination from the decaying corium.