Highly radioactive water is leaking into the sea from a 20-centimeter crack in a maintenance pit at Japan's crippled Fukushima Daiichi nuclear plant, its operator said on Saturday.
Tokyo Electric Power Co. said it was preparing to pour concrete into the pit under reactor 2 to try to stop the leak, NHK television reported.
Japan's nuclear watchdog said the crack could be the source of recent seawater contamination.
There could be other similar cracks, Hidehiko Nishiyama, deputy head of Japan's Nuclear and Industrial Safety Agency, told a news conference.
Japanese Prime Minister Naoto Kan made his first visit to area of northeaster Japan worst hit by the March 11 earthquake and tsunami earlier on Saturday. He visited an evacuee shelter and met with emergency crews battling to prevent massive radiation fallout at the nuclear plant.
The death toll from the quake and tsunami has neared 12,000, while nearly 16,500 remain unaccounted for.
TOKYO, April 2 (RIA Novosti)