Japan's Fukushima Daiichi nuclear power plant
The operator of Japan's Fukushima plant has admitted for the first time that a partial meltdown occurred in the station within hours after the March 11 twin disasters.
Tokyo Electric Power Co. (TEPCO) announced on Monday that based on new data, most of the fuel rods in the reactor No.1 had melted and fallen to the bottom of the reactor's pressure vessel only 16 hours after a massive quake and tsunami hit the plant.
"Because there is similar damage to the fuel rods at the No. 2 and 3 reactors, the bottoms of their pressure vessels could also have been damaged," senior TEPCO official Junichiro Matsumoto said.
Matsumoto added that the company plans to carry out similar analysis on the two reactors.
The massive March 11earthquake and ensuing tsunami in Japan's northeastern coast set off a nuclear disaster by knocking out power to the cooling systems of reactors at the Fukushima Daiichi plant, and caused radiation leaks.
The government initially ordered the evacuation of people living in a 20-kilometer (12.4-mile) radius around the plant, and told people residing between 20 and 30 kilometers (18.6 miles) from the plant to remain indoors.
On Sunday, Japan began widening evacuation zone around the plant and transferred about 4,000 residents of Iidate-mura village and 1,100 people in Kawamata-cho town to public housing, hotels and other facilities in nearby cities.
TEPCO has been struggling to stop radioactive leaks from the plant's damaged reactors for months.
On Thursday, the company said that new measurements taken this week indicate that water pumped into the pressure vessel had quickly leaked out from the reactor one building.
The company has also reported another spill of contaminated water despite efforts to stop spills into the Pacific.