Tokyo, Jul 22 (IANS): An aquatic robot introduced to the No. 3 reactor of the Fukushima nuclear plant in Japan has captured images of what appears to be melted fuel, with further exploration due to take place on Saturday, the plant's operator said.

Tokyo Electric Power Company (TEPCO) released images on Friday evening of a substance dangling like icicles around a control rod drive attached to the bottom of the pressure vessel, reports Efe news.

Further exploration will continue on Saturday at the bottom of the reactor vessel, which stands partially collapsed.

The remote-controlled aquatic robot was introduced on Wednesday in reactor No. 3, in an effort to locate fuel debris inside, an important step of the de-commissioning process.

Reactors 1, 2 and 3 experienced a partial nuclear meltdown due to failures of the cooling systems after an earthquake and tsunami in March 2011.

Knowing the exact status of the radioactive fuel rods is essential to handling and removing them.

Dismantling reactor No. 3 has been complicated by the extreme levels of radioactivity inside it.

It is believed that a large part of the reactor's uranium dioxide and MOX (a mixture of uranium and plutonium oxide) rods melted as a result of the accident and ended up at the bottom of the vessel.

The robot was introduced by the company on previous occasions to investigate the inside of the other two reactors but failed to assess the exact state of the fuel debris.