13 years after meltdown, the head of Japan’s nuclear cleanup is probing mysteries inside reactors

TOKYO (AP) — As Japan prepares to mark the 13th anniversary of its worst-ever nuclear disaster, the man in charge of cleaning it up says his team is fighting to bring a sample out of the heart of the site’s radioactive debris.

A decades-long project to clean up the remains of the Fukushima Daiichi nuclear power plant is preparing to remove damaged fuel debris from the plant’s reactors, but much about what’s inside them is still a mystery.

The key to unlocking that mystery — and figuring out how to clean it up — is a sample of melted fuel from inside a reactor, said Akira Ono, head of decommissioning for Tokyo Electric Power Company Holdings, in an interview with The Associated Press.

Getting that sample would be like penetrating “the main keep of the castle” in the battle of decommissioning, Ono said. “We have achieved a number of things, but we still have a lot of thinking to do to tackle the unprecedented task of removing melted fuel.”

A magnitude 9.0 earthquake and tsunami on March 11, 2011, damaged the Fukushima Daiichi plant’s cooling systems, causing three of its reactors to meltdown, releasing radiation and driving thousands of residents from their homes. Some areas near the plant are still unlivable.

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 from it using a robotic arm. That effort has been delayed for more than two years as the team works out how to