The coastal power plant, located 140 miles northeast of Tokyo, has been leaking radiation since a magnitude-9.0 quake on March 11 triggered a tsunami that engulfed the complex. The wave knocked out power to the system that cools the dangerously hot nuclear fuel rods.
The frantic effort to get temperatures down and avert a widening disaster has been slowed and complicated by fires, explosions, leaks and dangerous spikes in radiation. Two workers were burned after wading into highly radioactive water, officials said.
On Monday, workers resumed the laborious yet urgent task of pumping out the hundreds of tons of radioactive water inside several buildings at the six-unit plant. The water must be removed and safely stored before work can continue to power up the plant's regular cooling system, nuclear safety officials said.
Contaminated water inside Unit 2 has tested at radiation levels some 100,000 times normal amounts, plant operator Tokyo Electric Power Co. said.
Workers also discovered radioactive water in the deep trenches outside three units, with the airborne radiation levels outside Unit 2 exceeding 1,000 millisieverts per hour -- more than four times the amount that the government considers safe for workers, TEPCO said Monday.
New readings show contamination in the ocean has spread about a mile (1.6 kilometers) farther north of the nuclear site than before. Radioactive iodine-131 was discovered just offshore from Unit 5 and Unit 6 at a level 1,150 times higher than normal, Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, told reporters.
TEPCO officials said Sunday that radiation in leaking water in Unit 2 was 10 million times above normal -- an apparent spike that sent employees fleeing. The day ended with officials saying the huge figure had been miscalculated and was 100,000 times above normal, still very high but far better than the earlier results.