Smoke rises from Fukushima Daiichi 1 nuclear reactor after an explosion March 12, 2011 in this still image from a video footage. An explosion blew the roof off the unstable reactor north of Tokyo on Saturday, Japanese media said, raising fears of a disastrous meltdown at a nuclear plant damaged in the massive earthquake that hit Japan. REUTERS/NTV via Reuters TV (JAPAN – Tags: DISASTER IMAGES OF THE DAY ENERGY BUSINESS) NO ONLINE IN JAPAN. NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. TEMPLATE OUT. JAPAN OUT. NO COMMERCIAL OR EDITORIAL SALES IN JAPAN