13 Years After Meltdown, Head of Japan’s Nuclear Cleanup Is Probing Mysteries Inside Reactors

Debris inside the No. 1 reactor as a drone probes the worst-hit reactor at the wrecked Fukushima Daiichi nuclear power plant in Okuma town, northeastern Japan, on Feb. 28, 2024. TEPCO via AP

TOKYO—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.