Up to 8.5 tons of radioactive water have leaked from Japan's crippled Fukushima nuclear plant. TEPCO, the plant’s operator, failed to winterize the reactor’s cooling system, leading to fractures in its pipes due to frozen water inside.

­TEPCO claims that most of the leaked water is not radioactive, and has come from a dam. Though the company admitted that some of the water could be radioactive, it stressed that none of it has leaked to the sea.

Acknowledging its insufficient planning, TEPCO began replacing older pipes with new, plastic versions to prevent further leaks, while all leaks discovered so far have been stopped.

Many of the cooling system's pipes are exposed to the outside – and can run for several kilometers without insulation.

Some of the plant's workers reportedly informed TEPCO's managers about the possibility of such a problem during the summer.

“It was predicted that the pipes would freeze and cause water leakage,” said one TEPCO employee cited in fukushima-diary.com.

The Fukushima Daiichi nuclear power plant was damaged by a devastating earthquake and tsunami that hit Japan last March. Radiation leakage forced tens of thousands of people to leave their homes in and around the Fukushima region in central Japan.