TOKYO, March 20 (Xinhua) -- The operator of the crippled Fukushima Daiichi Nuclear Power Plant released newly captured drone footage on Thursday showing the bottom of the pressure vessel of the facility's No. 3 reactor.
The footage from Tokyo Electric Power Company Holdings (TEPCO) revealed a hole at the bottom of the vessel, with icicle-shaped adhesions that the company said may be melted nuclear fuel debris.
According to Kyodo News, the pressure vessel of the No. 3 reactor is made of steel, with an inner diameter of about 5.5 meters, and a base wall thickness of 14 cm.
The footage shows that part of the vessel's bottom section is missing due to core meltdown, exposing internal structures. Substances adhering to the surface are believed to be solidified nuclear debris formed after the meltdown.
Japanese media said that the footage marks the first time TEPCO has captured close-up images of the bottom of the pressure vessels from any of the No. 1 through No. 3 reactors in the Fukushima plant, all of which suffered core meltdowns after the six-reactor facility was hit by a 9.0-magnitude earthquake and an ensuing tsunami in 2011.
The meltdowns triggered a level-7 nuclear accident, the highest on the International Nuclear and Radiological Event Scale, and left behind an estimated 880 tons of nuclear debris.
The highly radioactive material poses significant risks, and its removal is widely regarded as one of the most formidable challenges facing the plant. The newly obtained images are expected to help inform future efforts to remove the debris.
TEPCO plans to begin full-scale debris removal at the No. 3 reactor in fiscal 2037 or later.
The Japanese government and TEPCO have set a target to complete decommissioning of the Fukushima Daiichi Nuclear Power Plant by 2051, though many experts and observers consider that timeline difficult to achieve. ■
