Posted April 21, 2015, NHK World:
” The operator of the Fukushima Daiichi nuclear power plant has issued a video of a robot stranded inside one of the damaged reactors.
The video released by Tokyo Electric Power Company on Monday shows the remote-controlled robot tilting to the right inside the containment vessel of the No.1 reactor.
The robot was sent inside the vessel on April 10th but stopped working after advancing just 10 meters. The utility has since given up on recovering the device.
TEPCO sent a second robot to retrieve the first robot. But the probe’s camera malfunctioned due to radiation exposure.
The utility decided to abandon both robot probes.
TEPCO says video footage shows no major damage to a part leading to the bottom of the containment vessel. Melted nuclear fuel fell on the vessel in the 2011 accident.
The operator says it will analyze the footage and other data to remove the fuel. ”
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Posted April 20, 2015, The Asahi Shimbun:
” The second shape-shifting robotic probe sent into the Fukushima No. 1 nuclear power plant has successfully surveyed the inside of a reactor after the failure of the first unit, the plant operator announced on April 16.
The robot was sent into the containment vessel inside the No. 1 reactor building on April 15 and scanned along an approximately 15-meter-long path, Tokyo Electric Power Co. said.
The machine was sent in to complete the mission of the first unit, which stalled April 10 just hours after it was sent inside the reactor.
The second robot measured radiation levels in three locations inside the containment vessel, which varied from a deadly 6.7 to 8.3 sieverts per hour.
The figures were similar to the measurements taken by the first robot, which read between 7.0 and 9.7 sieverts per hour in six locations.
All of those measurements indicate sufficient levels of radiation to kill a human in about one hour.
The identical robot units were developed by the International Research Institute for Nuclear Decommissioning to chart areas inside reactor containment vessels where humans cannot enter because of high radiation levels. Three reactors at the plant experienced meltdowns following the March 2011 Great East Japan Earthquake and tsunami.
Each robot is 60 centimeters long in its normal state, but can change shape depending on the space it is trying to enter. The probes are operated via connecting cables.
The utility plans to analyze the footage and radioactivity readings taken by the robots in hopes of utilizing the data when eventually removing the melted nuclear fuel from inside the building.
The second robot is scheduled to be retrieved on April 17. ”