situation is continuing to spiral downward. the first hint comes less than three hours later. the plant's cooling systems, absolutely vital to keeping nuclear fuel containable are not working. the japanese people and the rest of the world are warned to brace for the worst. just a few hours later, at 2:00 a.m. saturday among, radiation levels at reactor number one begin to climb. by dawn, radiation levels at the plant's main gate are eight times higher than normal. a very troubling sign. 12 hours later, at 6:22 p.m., the first of three major explosions transformed three of the reactor buildings into charred hulks of concrete. hydrogen most likely generated from the melting fuel rods has built up inside the buildings and then blown up. officials say no harmful gases were released by the explosion. nonetheless work the hours later, 200,000 people within 12 miles of the plant are asked to