'Special Report' revisits the story for the 'Whatever Happened To' series.
The plant's owner, Tokyo Electric Power Co. (TEPCO), predicts that decadeslong work to remove nuclear fuel, about 900 tons of melted fuel debris, dispose of contaminated cooling water and dismantle the four reactors will cost the government $76 billion or even more, according to Science Magazine.
"We’re still just very near the starting line" for cleaning up after the meltdowns and explosions triggered by the natural disasters, Fukushima prefecture Governor Masao Uchibori told reporters at a February press conference.
Details about what's happening inside the reactors are largely unknown because it is still too dangerous for humans to go inside and robots can only provide a partial view of the melted fuel.