LA Times – March 11, 2016 – Hiroshi Endo spent a decade building a robotic arm that Japan deployed to the International Space Station in 2010. But his next challenge made that one look easy.
In 2011, Endo, a 61-year-old retired engineer at Hitachi, the Tokyo-based mega-corporation, began designing a robot to aid in decommissioning the Fukushima Daiichi nuclear plant, the site of a meltdown that marked the worst nuclear crisis since Ukraine’s Chernobyl disaster in 1986.
In space, “you’ve got the sun, the moon, the Earth, temperatures. These are very definite, very specific — they’re not going to change,” Endo said. “But nuclear [reactors] are man-made. What’s going on inside the reactor is totally unknown, after the disaster. The operational environment is very different than space — it’s much harder.”
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Over the last five years, since an earthquake, tsunami and nuclear meltdown devastated a swath of Japan’s east coast, killing more than 15,000 people and displacing more than 230,000, the country has embarked on one of the most extensive recovery programs in history.
Robots have played a crucial role in Japan’s efforts to inspect, decontaminate and ultimately decommission the devastated nuclear reactors — a necessary step to regaining public trust and consigning the accident to history.
Experts say that more than 100 types of robots are active at Fukushima, including scores of modifications on a handful of basic designs. They’ve been likened to scorpions, snakes, giraffes and amphibians. They fly, walk, crawl and make underwater maneuvers, braving dust, debris and doses of radiation that could kill a human being. Their variety underscores the size — and complexity — of their task.
“The personnel exposure [to radiation] would be much higher without robots, and off-site releases would be much higher,” said Lake Barrett, an American nuclear energy expert who has consulted for top Japanese officials on the decommissioning program.
There are two types of robots, he said: “diagnostic robots,” which inspect the interiors of the buildings and reactors, and “working robots,” which do physical labor such as clearing debris and removing fuel rods.
“They have [robots] that shoot dry ice” to absorb radiation, he said. “Some shoot high-pressure water … some have carbide teeth that chip away at concrete surfaces, which are the most contaminated part, and suck the chips up in a vacuum cleaner.”
The decommissioning program is funded by the Japanese government and overseen by the International Research Institute for Nuclear Decommissioning, a Tokyo-based coordinating agency. The robots are built by scores of companies: Toshiba, Hitachi, Mitsubishi, BMW and the U.S.-based firm iRobot, best-known for developing the Roomba automated vacuum cleaner.
Much as the U.S. space program developed products that came to be used in everyday life, Barrett said that much of the technology developed to investigate the plants could be “spun off into regular society” — tiny cameras, tiny drones, virtual reality, technology that can transmit data through thick concrete walls.
Yet several engineers said that despite the difficulty of their work, widespread anger over the disaster has cast a pall over their public profile.
“One of the things that’s most interesting, that’s not really understood by the public, is the synergism between engineering technologies and social, political and psychological constraints,” Barrett said. “Engineers can do wonderful things with robots, etc. — and they do — but when it comes time to ask, how do we talk to people about this? How do we explain what the risks are? That’s a big challenge.”
The plant’s operator — the Tokyo Electric Power Co., also known as Tepco — has declared the situation at the plant stable. Thousands of employees still work there, pumping water into the devastated reactors to cool them and storing the contaminated water in massive tanks.