was too late. At 1:24 a.m., there was a tremendous roar, probably caused as a mixture of hydrogen and oxygen that had formed inside the reactor space suddenly ignited. The entire building shuddered as Reactor Number Four was torn apart by a catastrophic explosion, equivalent to as much as sixty tonnes of TNT. The blast caromed off the walls of the reactor vessel, tore open the hundreds of pipes of the steam and water circuit, and tossed the upper biological shield into the air like a flipped coin; it swatted
