Fukushima-Daiichi / Robot Retrieves Radioactive Fuel Debris from Unit 2

A remote-controlled robot has retrieved a tiny piece of melted radioactive fuel debris it collected from inside one of three damaged reactors at the Fukushima-Daiichi nuclear power station in Japan.

Tokyo Electric Power Company (Tepco), which manages the facility north of Tokyo, said the extendable fishing rod-like robot successfully clipped a piece of gravel of about 5mm from the top surface of a mound of molten fuel debris that sits at the bottom of the Unit 2 reactor’s primary containment vessel.

The “telesco” robot returned to an enclosed container for safe storage after workers in full hazmat gear pulled it out of the containment vessel.

An earlier operation to remove a small amount of fuel debris from Unit 2 was cancelled because of technical issues.

Tepco was aiming to retrieve just three grams of fuel debris as part of a demonstration programme for the unprecedented cleanup of the station, which is expected to take decades and cost about 23 trillion yen ($161bn, €145bn).

About 880 tonnes of fuel debris remain in the three reactors that suffered meltdown following the March 2011 earthquake and tsunami, according to estimates by the International Research Institute for Nuclear Decommissioning.

Tepco said that in Units 1, 2 and 3, the fuel and the metal cladding that forms the outer jacket of the fuel rods melted, then re-solidified as fuel debris.

“Fuel debris” refers to this melted fuel and other substances after they cooled and re-solidified.