By ANDREW MORSE And MITSURU OBETOKYO—Workers at Japan's damaged Fukushima Daiichi nuclear plant battled Monday to keep radioactive water that has flooded one reactor building from spilling over into the ocean, while the operator said plutonium was detected in samples of soil taken from the compound.
The plutonium discovery, along with readings of the contaminated pool, offered the strongest signs yet that the reactor's core may have partially melted. The new reports "back up the view that there was a partial melting of the fuel rods,'' chief government spokesman Yukio Edano said at a press conference on Tuesday morning.
Operator Tokyo Electric Power Co. said the plutonium was found at low levels that pose no risk to human health and are unlikely to affect the repair work. But the discovery is expected to add to the urgency of the task to bring the reactors under control.
Monday's events brought a new turn to the complex battle to stem disaster at the nuclear complex. Since the March 11 earthquake and tsunami knocked out cooling systems at the plant, the prime battle has been to bring overheating reactors down to safe temperatures. Last week, after crews doused reactors with salt- and freshwater, temperatures stopped rising.
Plant officials are now facing standing water in four of the complex's six reactor buildings, at least one of which is a pool of highly radioactive water. That poses dangers to personnel on the site and threatens to bedevil further work.