AmiMoJo writes: Radioactive water has leaked from a storage tank into the ground at Japan's Fukushima plant, operator TEPCO says. Officials described the leak as a level-one incident — the lowest level — on the International Nuclear and Radiological Event Scale (Ines), which measures nuclear events. This is the first time that Japan has declared such an event since the 2011 earthquake and tsunami. A puddle of the contaminated water was emitting 100 millisieverts an hour of radiation, equivalent to five year's maximum exposure for a site worker. In addition up to 300 tonnes a day of contaminated water is leaking from reactors buildings into the sea.