News Thirteen years after meltdown, Fukushima nuclear cleanup reveals mysteries

About 880 tons of highly radioactive melted nuclear fuel remains inside the three damaged reactors, but no one knows what condition the melted fuel is in or exactly where in the reactors it fell. That data is crucial to make a plan to remove it safely, said Ono. Since a 2019 robot probe first looked inside the No. 2 reactor — the least damaged — TEPCO has been trying to extract a small amount of melted debris using a robotic arm. That effort has been delayed for over two years as the team works to get the robot past the wreckage. Ono said the team's next attempt will come in October, using a previously tested device that resembles a fishing rod to get a preliminary sample out while waiting for technical improvements to the robotic arm. Last month, the plant flew its first drone into the worst-hit reactor, the No. 1 reactor, to investigate the melted debris. However, it had to cancel a second day of exploration after a secondary robot that helped with data transmission failed. "We are new to these things and sometimes encounter unanticipated mishaps on the ground. But they are all valuable lessons learned for our next steps," Ono said. Critics say the 30- to 40-year cleanup target set by the government and TEPCO is overly optimistic. The lack of data, technology, and plans on what to do with the fatally radioactive melted fuel and other nuclear waste at the end makes it difficult to understand how the plant complex and its surroundings may end up.

Click to expand...

The government and TEPCO have indicated that decommissioning the Fukushima nuclear plant will be completed by 2051, 40 years after the accident. However, experts are sceptical of this target. "I think achieving that will be difficult," one expert said. Developing the technologies needed to recover the debris has also been challenging. Initially, TEPCO planned to conduct a test to remove a few grams of debris from a reactor in 2021. However, the completion of a 22-meter-long robotic arm has been delayed, and in January 2024, the removal plan was pushed back for a third time. TEPCO aims to conduct this operation by around October using a fishing rod-type device with a proven track record.

Click to expand...