An underwater robot has captured images of massive deposits believed to be melted nuclear fuel that are covering the floor of a damaged reactor at Japan's crippled Fukushima nuclear plant.
Plant operator Tokyo Electric Power Co. said on Saturday solidified lava-like rocks heaped up from the bottom inside of a main structure called the pedestal that sits underneath the core inside the primary containment vessel of Fukushima's Unit 3 reactor.
Experts believe the melted fuel fell to the chamber's bottom and is now submerged by radioactive water.
The robot on Friday spotted suspected debris of melted fuel for the first time since the 2011 earthquake and tsunami destroyed the plant.
The three-day probe ends on Saturday.
Locating the fuel in each of the three wrecked reactors is crucial for the plant's decommissioning.
