AmiMoJo writes "The operator of the Fukushima Daiichi plant has been developing countermeasures to deal with repeated leaks from tanks of contaminated water. But despite the measures, 100 tons of radioactive water leaked on Wednesday and Thursday. 'The leaked water was among the most severely contaminated that Tepco has reported in the aftermath of the March 2011 disaster at the Fukushima Daiichi plant, when damage caused by an earthquake and a tsunami led to meltdowns in three of the plant’s reactors. Each liter of the water contained, on average, 230 million becquerels of particles giving off beta radiation, the company said. About half of the particles were likely to be strontium 90, which is readily taken up by the human body in the same way that calcium is, and can cause bone cancer and leukemia.' The estimated volume of the leaked radioactive materials caused Japan's nuclear regulator to rank the leak a level-3 serious accident. The international scale of nuclear and radiological events ranges from zero to 7."