In this Thursday, Feb. 5, 2015 file photo, a remote-controlled robot that looks like an enlarged fiberscope crawls down into the mock-up of a primary containment chamber of Fukushima Dai-ichi nuclear plant, during a demonstration for the media at a government facility in Hitachi, Ibaraki Prefecture, northeast of Tokyo. Tokyo Electric Power Co., the operator of the wrecked Fukushima nuclear plant, said Monday, April 13, the first robot, the same type shown in the photo, sent inside one of melted reactors stalled before finishing its work but it collected data that indicates a path to send robots deeper into the reactor is intact.