In a marriage of low and high technology, a robot is using a mop to clean up Japan's Fukushima Dai-ichi nuclear power plant.
Operator Tokyo Electric Power (Tepco) has modified a demolition robot and put it to work decontaminating the interior of the Unit 2 reactor building at the plant, which was crippled in the earthquake and tsunami that hit Japan in 2011.
The high radiation levels inside the reactor building, where nuclear fuel melted down, have impeded plans to decontaminate and decommission the facility, which is expected to take decades.
The robot is a DXR 140 demolition machine from Swedish robot maker Husqvarna that was modified by Toshiba for the Fukushima work. It has begun cleaning the walls and other surfaces in the building.
The machine moves around on treads and has a long arm that can rotate 360 degrees. It's equipped with 12 cameras, a dosimeter and a cabled remote-control system. Human operators control it from a safe distance where radiation levels are lower.
The machine itself is not equipped with radiation shielding.
At the end of its arm, the DXR 140 has a "chemical mop" resembling a kitchen sponge mop for cleaning surfaces. It also has a suction nozzle to suck up radioactive dust.
The machine will vacuum the building's walls, cable trays, ducts and control-panel surfaces, and will be deployed until mid-July.
"The robot is suitable for decontamination work in high places inside buildings as it has a long arm with an attachment which can reach as high as 5 meters," a spokeswoman for Tepco wrote in an email Thursday.
In a statement, the utility hailed the deployment of the robot as "a major milestone" ahead of full-scale decontamination and the eventual removal of damaged nuclear fuel from the reactor.
The DXR 140 follows other robots used at Fukushima Dai-ichi including Raccoon, a long, snake-like machine developed by ATOX of Japan, and PackBot, a military and law-enforcement robot from iRobot of Massachusetts.