Tons of highly radioactive water have flooded basements at the crippled Fukushima No. 1 nuclear power plant after pumps that should not have been in use were mistakenly turned on.
Plant operator Tokyo Electric Power Co. announced April 14 that 200 tons of contaminated water have flooded the basements of buildings on the plant site.
Although TEPCO officials said there were no channels for the contaminated water to leak out of the flooded basements, the Nuclear Regulation Authority ordered the utility to continue to monitor the situation and collect the leakage as soon as possible.
TEPCO officials said the water was highly contaminated because it was used to cool reactors at the Fukushima No. 1 plant. The water contains several tens of millions of becquerels per liter of radioactive cesium because it has yet to be purified using a system that removes radioactive materials.