Saturday March 11, 2017

Robots are piling up inside Fukushima's robot graveyard

Toshiba Corp's "scorpion" robot had to be abandoned in Fukushima's Unit 2 reactor when it ran into trouble. It was sent to investigate what happened to the radioactive fuel when the reactor melted down after the earthquake and tsunami that hit Japan in 2011.

Toshiba Corp's "scorpion" robot had to be abandoned in Fukushima's Unit 2 reactor when it ran into trouble. It was sent to investigate what happened to the radioactive fuel when the reactor melted down after the earthquake and tsunami that hit Japan in 2011. (The Associated Press/Shizuo Kambayashi)

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It's been six years since the triple meltdown at the Fukushima nuclear plant in Japan. Authorities in that country will soon allow more people to return to areas that had been evacuated in the wake of the disaster, but the areas within the damaged reactors are still off limits. They are too radioactive for humans to go near, which means clean-up efforts have been severely hampered. To deal with this problem, they have been sending in robots instead.

Dozens of tethered, remote-controlled bots have been used. Most of them are on tracks. However some are four-legged, boat, snake or scorpion-like robots. But so far, at least seven have broken down in there while trying to locate radioactive fuel, including two that just died in the last few weeks. One was pulled back after just two hours of a ten hour mission. Radiation had fried its camera. Another had to have its remote control cable snipped when it encountered something it couldn't get around. 

Dr. Jacopo Buongiorno is the the TEPCO professor of nuclear science and engineering, and associate department head, and director of the Center for Advanced Nuclear Energy Systems at MIT. He and his MIT colleagues are in discussions with TEPCO, the Tokyo Electric Power Company that supplies Fukushima with advanced robotics systems. He says the environment inside the reactors makes it difficult for the robots to complete their tasks because either obstacles are in their way or the radiation is affecting their camera systems or sensor silicon chips. At the moment, all the robots going into the containment vessel also have to squeeze through a ten centimetre air lock, which adds to the difficulty. Still, he sees this challenge as an opportunity to spur robotic innovation.