No. 3 unit of the Fukushima Daiichi Nuclear Power Plant, is seen, 2nd from right, with unit 1 reactor, left, with its top part of walls blown off after Saturday's explosion seen in Okumamachi, Fukushima Prefecture (state) , northern Japan Monday, March 14, 2011. Japanese officials say they believe a hydrogen explosion has occurred at the nuclear plant, similar to an earlier one at a different unit in the facility. (AP Photo/Kyodo News) JAPAN OUT, MANDATORY CREDIT, NO SALES IN CHINA, HONG KONG, JAPAN, SOUTH KOREA AND FRANCE