Photo released by Tokyo Electric Power Co.(TEPCO) shows a worker entering the building housing the No.2 reactor of the Fukushima No.1 nuclear power plant, on May 18, 2011. Workers trying to salvage the Fukushima No.1 nuclear power plant on Wednesday entered the building housing the No.2 reactor for the first time since an explosion took place inside the building in mid-March. [Photo/Xinhua]