TOKYO. For the first time since the 2011 nuclear disaster, a remote-controlled robot has safely extracted a tiny piece of melted nuclear fuel from inside one of the damaged reactors at Fukushima Daiichi, the nuclear plant severely affected by the tsunami-triggered meltdown.
According to Tokyo Electric Power Company Holdings (TEPCO), which manages the Fukushima plant, the robot successfully retrieved a piece of gravel roughly 5 millimeters in size—about the size of a granola bit—from the top of a mound of molten fuel debris at the bottom of Reactor No. 2’s primary containment vessel.
The robot, named “Telesco,” has a design resembling an extendable fishing rod equipped with tongs at the end. After collecting the sample, it returned safely to an enclosed container where TEPCO workers in full protective gear securely pulled it out on Saturday. This marks the first successful retrieval of melted fuel from within a reactor’s containment vessel.
However, the mission is ongoing as TEPCO needs to confirm the sample’s radioactivity levels. If the sample’s radioactivity exceeds set limits, Telesco will need to re-enter the containment area to find another piece. “We expect the sample’s size to meet the requirement, but verification is crucial,” TEPCO officials stated.
The mission, initially scheduled as a two-week operation starting in August, faced delays due to procedural and technical issues. In one instance, an error during preparation held up the mission for nearly three weeks. Later, both of the robot’s cameras failed, preventing operators from viewing target areas remotely, necessitating the robot’s withdrawal for repairs. The operation resumed last Monday after camera replacements.
Since the catastrophic 2011 earthquake and tsunami, which destroyed Fukushima Daiichi’s cooling systems and led to meltdowns in three reactors, TEPCO has worked to develop advanced robotic technology for plant decommissioning. The disaster left an estimated 880 tons of highly radioactive fuel inside the reactors, posing an ongoing challenge for TEPCO’s decommissioning efforts.
On Wednesday, Telesco successfully clipped a small sample weighing less than 3 grams from underneath Unit 2, where large amounts of melted fuel debris have been lodged since the accident. “This tiny piece of fuel debris provides key data that will inform our decommissioning strategy, guide new technology development, and help us understand how the accident unfolded,” said plant chief Akira Ono.
Japan’s government and TEPCO have targeted a 30-to-40-year timeframe to fully decommission Fukushima Daiichi, although experts caution that this estimate may be overly optimistic given the complexity and high-risk nature of the task. Plans for the complete removal and final disposal of the fuel debris remain undecided.
Gary P Hernal started college at UP Diliman and received his BA in Economics from San Sebastian College, Manila, and Masters in Information Systems Management from Keller Graduate School of Management of DeVry University in Oak Brook, IL. He has 25 years of copy editing and management experience at Thomson West, a subsidiary of Thomson Reuters.
