”Now that the buildings themselves are more under control, they need to go into the reactors and assess and then remove the fuel,” Padir said. "They need to collect all of that radioactive fuel. Since this is a full shutdown, they need to remove all the fuel in there. They went in and progressed a little bit but were they successfully able to complete the entire mission? No."
Tepco reported last month that a Scorpion robot, developed by Toshiba and the IRID, was on a mission to investigate temperatures and radiation levels in a damaged reactor when it got stuck. The connection cable to the robot was cut and it was abandoned.
Earlier this month, Tepco reported that one robot got stuck in a grating ditch while on its way to performing an inspection.
A lesson learned from that incident, the company said that a laser will be installed on future robots to improve their spatial ability, as well as to enable the machines to check for obstacles and openings while moving. Another robot was lost because radiation caused its camera screen to fail, Tepco said.
A snake-like robot built by Hitachi-GE was lost in 2015 when it was sent in to inspect a nuclear containment vessel, according to a report from the International Business Times. It's unclear why the robot stopped responding but it, too, was abandoned.
These failures are concerning because they are happening at the most critical part of the cleanup.
"Those robots were going into the most damaged reactors,” Padir said. "From a broader perspective, those robots are the most critical. They’re trying to go to an environment where no other robot or no other person could go. There is no way to test your systems in advance. You just have to go in and see what happens. You won’t know how it will perform or what will happen until you send the robot in."
Scientists have already been working on robots that can aid in disaster situations. The 2015 DARPA Robotics Challenge demonstrated two-legged humanoid robots that could climb stairs, walk over piles of rubble, use drills, climb ladders and drive cars, among other tasks. But more research needs to be done before these robots will be ready to aid in such disasters.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, said scientists have learned a great deal from the robotics work being done at Fukushima.
MIT researchers are talking with Tepco about a project to develop advanced robots that would overcome the issues their predecessors have had at the power plant site.
Ideas range from robots that use legs instead of tracks, robots that combine walking with swimming, and robots with higher levels of radiation protection.
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