The Tokyo Electric Power Co. says almost all the nuclear fuel in one of its reactors at the Fukushima plant has melted. The discovery at Reactor 1 should help with the clean-up operation and decommissioning of the stricken nuclear power station.
The Tokyo Electric Power Co. (TEPCO) and the International Research Institute for Nuclear Decommissioning (IRID) have been working since February, studying the interior of the reactor building at the Fukushima No. 1 nuclear plant.
TEPCO, which is in charge of operating the plant, used cosmic rays to inspect the reactor building. By analyzing the flow of muons, which are subatomic particles generated when cosmic rays collide with the atmosphere, the utility was able to create an X-ray like image of what the inside of the reactor looks like.