This still image taken from news program by NHK on March 14, 2011 shows the Fukushima No. 1 nuclear power station before (bottom) and after (top) a hydrogen explosion of the No. 3 nuclear reactor. Japan's Nuclear and Industrial Safety Agency said Monday that hydrogen blast occurred at the No. 3 nuclear reactor of Fukushima No. 1 nuclear power plant at 02:01 GMT (11:01 local time). [Xinhua/NHK]