Nature

Robots Designed to Clean Up Fukushima Reactors Have "Died"

March 14, 2016 | Joanne Kennell

Robot designed to collect fuel rods at the Fukushima site

Photo credit: Screenshot from video by The Japan Times

As soon as they got too close to the reactors, the radiation destroyed their wiring.

March 11 marked the five-year anniversary of the devastating magnitude 9.0 earthquake — one of the most severe in recorded history — that triggered a massive 10-meter (33-foot) high tsunami that hit the northeastern coast of Japan. It killed nearly 20,000 people and damaged four reactors at the Fukushima Daiichi nuclear power plant.

Clean up efforts have been slow since nuclear radiation exposure to humans can be fatal. “It is extremely difficult to access the inside of the nuclear plant," Naohiro Masuda, Tepco's head of decommissioning said in an interview with NewsWeek. "The biggest obstacle is the radiation.”

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However, in order to clean up the dangerous mess, Japan built robots designed to swim through the underwater tunnels of the now non functioning cooling pools, and remove hundreds of extremely dangerous blobs of melted fuel rods — which have melted through their containment vessels.

Sounds promising, right?

Unfortunately, these remote-controlled robots are “dying” as they approach the uranium oxide rods due to high amounts of leaked radiation still leaking from the plant which destroys their wiring.

Although the plant’s operator, Tokyo Electric Power Co (Tepco), has made some progress with the robots by removing over a thousand fuel rods in one damaged building — where radiation levels were lower — only 10 percent of the debris has been cleaned up.

“Efforts to clean up Fukushima, which is considered the largest nuclear disaster since the Chernobyl accident in 1986, are under continued scrutiny after a series of blunders and Tepco's admission that efforts in the short term to contain contamination may take as long as 30-40 years,” Peter Dockrill told ScienceAlert in January, when the robots were first deployed.

Unfortunately, it is not as easy as sending in a new robot after one dies because each one was customized for the job at hand and took two years to build. It turns out, no robot will be able to withstand this amount of radiation because the technology just doesn’t exist.

Tepco is currently building the world’s largest “ice wall” around the plant to stop the nearby groundwater from being contaminated, but it is not yet complete. However, it does not clean up the mess — it just contains it.

“The reactors continue to bleed radiation into the ground water and thence into the Pacific Ocean,” Artie Gunderson, a former nuclear engineer who is not involved in the project, explained to NewsWeek. “When Tepco finally stops the groundwater, that will be the end of the beginning.”