Breakthrough at Fukushima: Robot retrieves melted nuclear fuel fragment 13 years after tsunami disaster

More than a decade after the Fukushima Daiichi disaster sent shockwaves around the world, a new milestone has emerged from the rubble — Tokyo Electric Power Company’s (TEPCO) groundbreaking robot successfully grabbed a tiny piece of melted nuclear fuel, a small but significant step in the colossal task of decommissioning the plant.

The 2011 Fukushima disaster: What happened?

On March 11, 2011, a powerful 9.0-magnitude earthquake struck off the coast of Japan, triggering a massive tsunami that swept over the northeastern coast of the country. The Fukushima Daiichi Nuclear Power Plant, located in this area, was hit hard by the tsunami. This disaster caused the plant’s critical cooling systems to fail, leading to a series of meltdowns in three of its reactors. The meltdown resulted in the release of hazardous radioactive materials into the air and surrounding environment, forcing the evacuation of nearby residents and creating a serious health and environmental crisis.

The accident left an estimated 880 tons of radioactive fuel debris inside the plant’s damaged reactors. This highly radioactive material solidified into a dangerously unstable mixture, requiring years of preparation and research to safely begin removal.

The role of the ‘Telesco’ robot

For the first time since the disaster, TEPCO has successfully extracted a sample of this molten fuel using a specialised robot called "Telesco." Shaped somewhat like a fishing rod, Telesco was equipped with tongs at its end to grip a piece of debris no larger than a granola bit. Despite being only about 5 millimetres in size, this small piece represents a significant achievement, as it marks the first physical retrieval of melted fuel from the reactor since 2011.

This mission wasn’t without its challenges. Initially planned to take only two weeks, the operation faced several delays. Early on, a procedural mistake paused the mission for nearly three weeks. Later, the robot’s cameras — which operators relied on for navigation — failed, forcing the robot to be removed from the reactor for repairs. Once these technical issues were resolved, Telesco was able to carefully clip a small piece of the fuel from a mound of molten debris on the bottom of the Unit 2 reactor.

Why this small sample matters

TEPCO officials emphasise that even this tiny piece of fuel debris could provide crucial data to help refine the decommissioning strategy for the plant. Testing the radioactivity levels of the sample will help researchers understand the current condition of the melted fuel. By studying it, scientists hope to improve robotic technology and techniques for dealing with radioactive material and gain insights into the meltdown’s progress, making future retrieval operations safer and more effective.

This success may also boost confidence in TEPCO’s long-term decommissioning plans, though experts caution that the target timeline of 30-40 years might be overly optimistic given the scale of the remaining work. TEPCO has not yet outlined a concrete plan for the complete removal or disposal of the fuel debris, but ongoing technological advances may soon bring a clearer path to resolution.

Challenges and the road ahead

The Fukushima cleanup effort is one of the most complex nuclear decommissioning projects in history, requiring significant innovation. Robots like Telesco are vital, as high radiation levels prevent human workers from entering the reactors directly. However, each small success comes with a new set of challenges, including handling the radioactive material and finding safe, long-term storage solutions.

In the future, TEPCO plans to continue developing and deploying robotic technologies to safely retrieve and manage the remaining fuel. While full decommissioning might take longer than initially projected, the commitment to advancing nuclear safety and managing past mistakes remains strong.