30 June 2018
Scientists have finally been able to find Fukushima reactors melted core with the help of new robots called Mini-Manbo, or “little sunfish. The new robots are made of a radiation-hardened material with a built-in sensor that helps in avoiding dangerous hot spots in the plant’s flooded reactor buildings.
The mini-robots transmitted a direct view of melted radioactive fuel inside Fukushima Daiichi Nuclear Power Plant’s destroyed reactors. It took six long and painful years before the core of the reactor was discovered.
Till now many robots have been sent to the reactor, but all of them have faced major setbacks, which has led to a delay in the clean up of the destroyed reactors. Japanese electrical utility Tepco’s timetable to start removing the highly radioactive fuel and continued leakage of radioactive substances has faced a major setback due to this.
The robot navigated for three days through the shattered reactor building and finally reached the heavily damaged Unit 3 reactor. The robot beamed back video of a gaping hole at the bottom of the reactor which looked like solidified lava. These are the first images ever taken of the plant’s melted uranium fuel.
“Until now, we didn’t know exactly where the fuel was, or what it looked like,” said Takahiro Kimoto, a general manager in the nuclear power division of the plant’s operator, Tokyo Electric Power Co., or Tepco. “Now that we have seen it, we can make plans to retrieve it.”
At the plant’s entrance, a sign warned: “Games like Pokemon GO are forbidden within the facility. We have finished the debris cleanup and gotten the plant under control,” said the guide, Daisuke Hirose, a spokesman for Tepco’s subsidiary in charge of decommissioning the plant. “Now, we are finally preparing for decommissioning.”
“They are being very methodical — too slow, some would say — in making a careful effort to avoid any missteps or nasty surprises,” said David Lochbaum, director of the nuclear safety project at the Union of Concerned Scientists. “They want to regain trust. They have learned that trust can be lost much quicker than it can be recovered.”