Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster

by Adam Higginbotham

Valery Legasov and the team of scientists analyzing the latest data from Unit Four had made a horrifying and apparently inexplicable discovery. Instead of continuing to fall, the radioactive releases from the reactor had now suddenly begun to increase again, doubling from 3 million to 6 million curies overnight. The temperature of the burning core, too, was rising rapidly. By Thursday night, Legasov’s estimates suggested that it was already approaching 1,700 degrees centigrade. The academicians now feared that the uranium dioxide fuel and zirconium cladding remaining inside the vault of Reactor Number Four had become so hot that they had started to fuse into a mass of radioactive lava in what amounted to a total core meltdown. Worse still, the 4,600 tonnes of sand, lead, and dolomite that had been flung into the damaged building from two hundred meters in the air, combined with the impact of the initial explosions a week before, might have fatally compromised the foundations of the reactor. If the temperature of the molten fuel reached 2,800 degrees centigrade, they suspected it could begin burning through the reinforced concrete floor of the reactor vault. Pressed down from above, it could eat its way through the bottom of the vault, into the basement of the building, and deep into the earth below. This was the doomsday scenario of reactor accidents: the China Syndrome.