NHK has learned it is highly likely that a large amount of melted nuclear fuel remains at the bottom of one of the damaged reactors at the Fukushima Daiichi nuclear power plant.

Experts from Tokyo Electric Power Company and other institutions confirmed a large black shadow at the bottom of the No.2 reactor, using a device that uses elementary particles called muons.

The probe to see into the reactor’s interior has been conducted with the High Energy Accelerator Research Organization and others.

The analyses of the image led the experts to believe that most of the melted fuel is likely located at the bottom of the reactor together with other structures in the reactor.

This is the first time that an image of what’s believed to be molten fuel has been captured. Similar shadows are said to have been confirmed also on the walls of the reactor.

The results of the probe have a considerable impact on a process to remove melted fuel, the most difficult part of reactor decommissioning.
TEPCO is conducting further analyses of the reactor.

During the accident in 2011, nuclear fuel melted down in the plant’s 3 reactors. Most of the fuel in the No.1 reactor is believed to have melted through the core. But the locations of the fuel in the No.2 and 3 reactors are not yet known.