Precarious Japan nuclear plant raises safety concerns

Tokyo: Recent problems at Japan's crippled nuclear power plant are highlighting its precarious state two years after it was damaged by a massive earthquake and tsunami.

Nuclear Regulation Authority Chairman Shunichi Tanaka says the plant, which relies on makeshift cooling systems for its broken reactors, remains highly vulnerable.

Tanaka said Wednesday that leaks of radioactive water from underground tanks are undermining efforts to decommission the plant. The tanks store massive amounts of water used to cool the reactors.

The plant's operator says three of the seven underground tanks are leaking, but that the contaminated water is not believed to have reached the ocean. However, experts suspect that water has leaked steadily into the sea since early in the crisis, citing high radiation levels in fish in waters off the plant.