Water releasing as much as 10 trillion becquerels of radioactive strontium and 20 trillion becquerels of cesium-137 from the Fukushima No. 1 power plant has flowed into the Pacific Ocean since May 2011, Tokyo Electric Power Co. estimates.
The combined figure of 30 trillion becquerels, announced late Wednesday, implies that highly radioactive water is entering the trenches under the damaged reactors' turbine buildings.
The three reactors that had core meltdowns are being flooded by emergency cooling water needed to keep the leaky units stable, but the water is leaking from the reactors into the basements, where it is mixing with groundwater penetrating the walls of the 40-year-old plant.