TOKYO - A “scorpion” robot sent into a Japanese nuclear reactor to learn about the damage suffered in a tsunami-induced meltdown had its mission aborted after the probe ran into trouble, Tokyo Electric Power company said Thursday.

TEPCO, the operator of the Fukushima nuclear plant, sent the remote-controlled device into the No. 2 reactor where radiation levels have recently hit record highs. The “scorpion” robot, so-called because it can lift up its camera-mounted tail to achieve better viewing angles, is also designed to crawl over rubble inside the damaged facility. But it could not reach its target destination beneath a pressure vessel through which nuclear fuel is believed to have melted because the robot had difficulty moving, a company spokeswoman said. “It’s not immediately clear if that’s because of radiation or obstacles,” she said, adding that TEPCO is checking what data the robot was able to obtain, including images.

A massive undersea earthquake on March 11, 2011 sent a huge tsunami barrelling into Japan’s northeast coast, leaving more than 18,000 people dead or missing, and sending three reactors into meltdown at the plant in the worst such accident since Chernobyl in 1986. The Japanese government said in December that it expects the total costs - including compensation, decommissioning and decontamination - to reach 21.5 trillion yen ($189 billion) in a process likely to take decades as high radiation levels slow operations.