An icicle that appears to be melted nuclear fuel has been seen hanging from the bottom of the pressure vessel of the No. 3 reactor at the crippled Fukushima No. 1 nuclear power plant, sources said.
Tokyo Electric Power Co., the plant's operator, confirmed the presence of what is believed to be fuel debris on July 21 with an underwater robot equipped with a camera, the sources said.
If the icicle is confirmed to be fuel debris, it will become valuable data in the investigation to determine the cause of the accident, triggered by the March 2011 Great East Japan Earthquake and tsunami, and efforts to decommission the reactor.
The survey of the No. 3 reactor conducted so far has found that most of the nuclear fuel apparently melted and fell through a hole at the bottom of the pressure vessel.
On July 21, TEPCO deployed the underwater robot into the No. 3 reactor’s containment vessel, which holds the pressure vessel, from early in the morning to look into the area below the pressure vessel.
When the robot entered the area, its camera showed what seems to be fuel debris hanging like an icicle from a hole at the bottom of the pressure vessel.