As a preventative step, workers at the crippled Fukushima Da-ichi nuclear power plant, about 250km northeast of Tokyo, were pumping accumulating rain water pooling around hundreds of storage tanks containing radioactive water into the ocean. They are trying to avoid the risk of potential tank leaks getting mixed with rainwater seeping into the soil or flowing into the sea.
Plant operator Tokyo Electric Power said it released what was believed to be untainted rainwater into the Pacific Ocean in order to avoid flooding near the tanks - a step that could violate safety rules, the Nuclear Regulation Authority said. TEPCO says the radioactivity in the released water was within allowed discharge limits, but duty regulators at the plant were checking.
Recent acknowledgement by officials that contaminated water is leaking from underground and storage tanks into the ocean have triggered concerns about the plant's safety.
Read back a few articles here, as it doesn't take rocket science to see that this would be done....