The operator of the damaged Fukushima nuclear plant has suspended a preliminary survey using a robot inside the containment vessel of one of its reactors.
On Thursday, a remote-controlled robot was sent toward the middle of the No. 2 reactor, but the operation was later suspended after images captured by one of the robot's 3 cameras turned out black.
The survey is part of efforts toward decommissioning the No.1 to No. 3 reactors, which suffered meltdowns.
Officials of Tokyo Electric Power Company say they will find out what went wrong before deciding how to proceed with the survey. The utility originally planned to use the same robot on Tuesday, but put it off to Thursday due to mechanical trouble.
The exact conditions inside the containment vessel must be determined before a full survey can be undertaken. The full survey will use a scorpion-shaped robot to measure radiation levels and temperatures.
A remote-controlled camera used in a survey last week captured footage of what seemed to be debris of molten fuel on the partially broken floor grate in the vessel.