It’s one of the greatest, and most disturbing, questions of the Fukushima disaster: What happened to the nuclear fuel inside the plant? Now physicists are trying to shed some light on the problem using particles from the edge of space.
The Fukushima accident was broadcast around the world. On March 11, 2011, an earthquake and tsunami struck the plant, knocking out cooling in three working reactors. The uranium fuel inside melted down.
But nobody’s quite sure where it went.
Above: A computer simulation (left) shows how muons would image the pill-shaped vessel of the Fukushima Unit 1 reactor. An actual muon image (right) taken across 26 days is considerably fuzzier; but, judging from the lack of shadowing in the center, the nuclear core appears to be gone, engineers say. Better muon detectors might help figure out where it went. Images: Courtesy of TEPCO