TOKYO (Nikkei)--The Nuclear and Industrial Safety Agency (NISA) said Saturday afternoon the explosion at the Fukushima No. 1 nuclear plant could only have been caused by a meltdown of the reactor core.
The same day, Tokyo Electric Power Co. (9501), which runs the plant, began to flood the damaged reactor with seawater to cool it down, resorting to measures that could rust the reactor and force the utility to scrap it.
The core of a nuclear reactor damaged by Friday’s massive earthquake has partially melted, Japan’s nuclear safety agency said Saturday, and the company that runs the plant is pouring seawater into the reactor in an attempt to cool it and prevent it from going critical.
Early Sunday, Japan's nuclear safety agency reported an emergency at a second reactor in the same complex.
The Nuclear and Industrial Safety Agency said that the cooling system malfunctioned at Unit 3 of the Fukushima Daiichi nuclear plant No. 1. The agency said it was informed of the emergency by Tokyo Electric Co., or TEPCO, the utility that runs the plant.
No further details of the troubles at Unit 3 were immediately available.
An explosion Saturday at the same plant destroyed the exterior walls of a building, but officials said the blast did not breach the steel housing enveloping the reactor there.
TEPCO's Fukushima No. 1 and No. 2 plants lost their cooling functions after the area was jolted by a magnitude 8.9 earthquake on Friday. Radioactive cesium and iodine were detected near the facility Saturday, indicating that the melting had occurred, Kyodo News Service reported.
Explosion at Japan nuclear plant (Update 3/14/11)
Japan's nuclear crisis has deepened after a second reactor building at the Fukushima Daiichi atomic power plant exploded on Monday morning. Officials said there was a low possibility that the blast had released radioactive material into the air.