A remote-controlled camera captured what appears to be melted fuel inside a reactor of the stricken Fukushima No. 1 nuclear power plant, operator Tokyo Electric Power Co. said.
The released footage showed pebble-like nuclear fuel debris and part of a nuclear fuel assembly scattered at the bottom of a containment vessel, located just below the pressure vessel.
The footage was taken Jan. 19 inside the No. 2 reactor, which went into meltdown due to the 2011 earthquake and tsunami disaster.
“From the look of things, it must be nuclear fuel debris,” said a TEPCO official.
The utility inserted an extendable rod with a span of 16 meters into the containment vessel from an opening in the side. It was positioned in an area just below the pressure vessel.
The remote-controlled camera was affixed to the tip of the rod and then lowered, along with a dosimeter to measure the amount of radiation inside.
The footage showed that a handle for a 4-meter-long nuclear fuel assembly, which had been originally located in the pressure vessel, had dropped to the bottom of the containment vessel.
The handle had been installed on the top of the nuclear fuel assembly. This led TEPCO to conclude that all of the nuclear fuel below the handle had melted.
An accumulation of pebble-like materials around the handle prompted the official to remark that the same phenomenon was observed after the Three Mile Island nuclear accident in Pennsylvania in 1979.
"(What we found this time) is apparently the same situation,” the official said.