In 2011, a 9.0 magnitude earthquake off the coast of Japan caused a massive tsunami, which in turn led to the meltdown of three nuclear reactors at the Fukushima Nuclear Power Plant in Fukushima, Japan. As a result, the site went on to release radioactive material for the next three days, becoming only the second such disaster in history–after Chernobyl in 1986–to be classified a Level 7 event on the Nuclear Event Scale.
So perhaps it should come as no surprise that, just past the tragedy’s six year anniversary, Tokyo Electric Power Co. (Tepco) has made little progress in cleaning up the disaster site.
While Tepco has spent much of its time containing radiation and attempting to minimize groundwater contamination, its current mission is to locate and retrieve 600 tons of melted nuclear fuel rods lost somewhere in the radioactive wreckage. As the levels of radiation are still too high for human exposure, this task has fallen to robots. Yet so far, even the robots have failed repeatedly to locate the melted fuel rods; instead, they are dying within the reactors they were sent in to survey.
The latest device to meet its end was a scorpion-shaped robot built by Toshiba, which entered one of the reactors last month but stalled just 10 feet short of its target in a matter of hours. While it was ultimately undone by the failure of its left roller-belt, the robot was exposed to far higher than expected levels of radiation, which likely interfered with its electronics and prevented it from sending photos that could have shed some light on the location of the melted fuel rods.
Despite being manufactured using special radiation-hardened materials to protect its circuits from exposure, the levels of radiation it encountered within the reactor far exceeded the robot’s tolerance. Two prior robot missions had to be aborted as well after one got stuck and another failed to locate any melted fuel for several days.