plant about 170 miles north and east of our location here in tokyo. workers are having trouble with several reactors there. these are the reactors in question. before the disaster. on saturday a hydrogen explosion blew the roof off and wall containment building unit number 1. that triggered the evacuation of some 185,000 people. on monday, another explosion hit their unit 3. as workers tried to cool the reactor core with sea water. but the real problem now is in unit number 2. officials say water levels there have dropped not once but twice leaving the uranium fuel rods out in the open. >> the water level did start to fall and the fuel rods were exposed above the water. >> shepard: and without water covering it, the uranium can heat to temperatures of 5,000 degrees fahrenheit. the fear is that the uranium could then burn right through the containment chamber and