Why it matters: Robots have been crucial to the cleanup of the Fukushima Daiichi nuclear power plant, which was destroyed in 2011 by an earthquake and subsequent tsunami. The machines have saved human workers from radiation exposure by going into areas otherwise accessible. Now, Tokyo Electric Power Company is embarking on its next stage of robotics use: the removal of melted fuel.
On March 11, 2011, disaster struck Japan's Fukushima Daiichi nuclear power plant when a powerful earthquake and subsequent tsunami hit the Tohoku region of Japan, killing 15,900 people. The 50-foot tall waves hit the nuclear power plant, destroying its diesel generators that powered the coolant-circulating pumps, resulting in three nuclear meltdowns, three hydrogen explosions, and widespread radioactive contamination at the site.
Since then, operators have deployed robots to explore inside the reactor buildings and to convey images back to engineers, reducing their risk of radiation exposure. For example, the quadruped robot Spot, developed by Boston Dynamics, has collected data, shot video, measured radiation doses, and gathered debris samples for radiation testing. Drones are not ideal for these tasks because their rotor blades can kick up dust and debris, spreading contaminated materials.
While Spot has proven helpful for many tasks, Tokyo Electric Power Company Holdings (TEPCO) has long known that decontaminating the high-dose radiation area inside the reactor buildings and removing fuel debris from the reactor would require a specialized robot. The day for those next-level tasks is approaching, and engineers finally have a bot for the job after two years of delays.
This week, TEPCO demonstrated a robot equipped with tongs used to retrieve tiny bits of melted fuel debris from the three damaged reactors. In the demo, the robot slowly descended from a telescopic pipe to a pile of gravel and picked up a stone.
Crews will put the robot to use later this year in one of the reactors, marking the first attempt to remove melted fuel contamination from the site since the 2011 disaster. About 880 tons of highly radioactive melted nuclear fuel remain at the site. The cleanup crew will remove less than 3 grams of debris in a test at reactor 2. Researchers wish to study the melted fuel debris before TEPCO proceeds with the decommissioning.
Japan reveals new robot to clean up melted fuel at Fukushima