Frantic efforts to contain radioactive leaks at the wrecked Fukushima Daiichi nuclear power plant have been dealt another blow after its operator said about 300 tonnes of highly contaminated water had seeped out of a storage tank at the site...Tokyo Electric Power Co (Tepco) said it did not know how the water leaked out or where it had leaked to, but it believed that the spillage had not flowed into the Pacific ocean. Tepco...said the water had seeped into the ground after breaching a concrete and sandbag barrier around the tank. Workers were pumping out the puddle and removing the remaining water from the tank, he added. Despite efforts to contain the spillage, the leak is already the most severe since the crisis began.