Nuclear news directly from Japan is very hard to come by since the Japanese government passed the State Secrets Bill, which allows journalists to be sentenced to up to ten years in prison for revealing anything the government decides it doesn't want the world to know. In light of the Tokyo Summer Olympics coming up in 2020, one of the chief things the government doesn't want the world to hear about is what is (or isn't) happening at the Fukushima Daiichi nuclear power plants. But a startling revelation has leaked out nevertheless - the fuel from the Fukushima Daiichi Reactor No. 2 is missing.
Scientists, engineers, public safety officials, and environmentalists have long wondered exactly what happened inside the three reactors that melted down after the March, 2011 earthquake and subsequent tsunami. A number of robots have been specially designed to investigate the plants, but radioactivity is so high the robots have all fried before getting far. (So much for the idea that nuclear disasters could be cleaned up by robots...).
However, researchers from Los Alamos National Laboratory, Lawrence Berkeley National Laboratory, and the University of New Mexico came up with a novel idea - essentially, view the reactors from outside the structures; a sort of cosmic ray "C.T." scan measuring the muons that passed through the reactors. Researchers from Nagoya University tested the technique on reactor No.5, and the fuel in the core of that reactor was clearly visible. "However, at No. 2 reactor, which released a very large amount of radioactive substances coincident with the 2011 explosion, little, if any, signs of nuclear fuel appear in the containment vessel." The researchers reported their findings at a meeting of the Physical Society of Japan on September 26th.
If the fuel is not in the containment vessel, the situation is dire - where is it? That is the (literally) trillion dollar question, as it was already looking like that was what the cost of the cleanup would be before this latest 'twist'.
Assuming a cleanup is even possible. So far all that has been done at the reactors themselves has been removing debris from around and on them and removal of most of the spent fuel from the pool on top of one ("undamaged") reactor. Mostly all they can do is pour water on them to keep them cool, creating an ever-expanding tank farm of radioactive water they filter the best they can before dumping it in the ocean.
We can only speculate as to where this fuel is, hoping it remains in the reactor building. Particularly worrisome are water-soluble radionuclides like Cesium 137. Only 1.2 grams of Cs-137 per square mile forced Russia to declare over a thousand square miles of land uninhabitable for centuries.
And of course the question remains, what about the fuel in the other two reactors that melted down?
(Update: In looking for the missing primary sources, I found mention that the same viewing process was previously used by a different team on Reactor No. 1, with the same result - the fuel is not in the containment vessel.)