Japan fears nuclear reactor core breach

Japanese officials have expressed alarm over a possible fracture of a reactor core

at one unit of the troubled Fukushima Daiichi nuclear power plant.
Japanese nuclear safety officials raised the possibility of more severe environmental contamination on Friday with their latest announcement on the country's nuclear crisis.

Radioactive fallout from Fukushima reaching same levels as Chernobyl.

Lack of data from Japan distresses nuclear experts.