Tokyo Electric Power on Friday sent a robot where no machine has gone before—inside the highly radioactive heart of a reactor at the crippled Fukushima Dai-Ichi nuclear power plant.

The robot, developed by Hitachi-GE Nuclear Energy and the International Research Institute for Nuclear Decommissioning (IRID), was inserted into the primary containment vessel (PCV) of reactor No. 1 at the plant, which was heavily damaged by the 2011 earthquake and subsequent tsunami that devastated northern Japan.

Tokyo Electric is taking the unprecedented step to better determine the state of melted-down fuel in the reactor as part of plans to dismantle the plant, a spokesman said. The No. 2 and No. 3 reactors also suffered meltdowns.

To read this article in full or to leave a comment, please click here