Tokyo Electric Power Company Holdings (TEPCO) announced on Saturday that the robot, equipped with extendable fishing rod-like capabilities, managed to cut a piece of debris approximately the size of a granola bit, measuring about 5 millimeters (2 inches), from the pile of melted fuel situated on the floor of the Number 2 reactor’s primary containment vessel.
The robot, dubbed “Telisco,” safely returned to its storage container with the melted fuel piece still attached to its front pincers, after workers in full hazardous gear extracted it from the containment vessel earlier that morning.
A Historic Milestone
This sample retrieval represents the first time melted fuel has been extracted from a containment vessel since the disaster. However, the mission will not be complete until the radiation levels of the sample are confirmed to be below established safety standards. If the radiation is found to be above the limit, the robot may have to re-enter the reactor to locate another piece. TEPCO officials expressed optimism that the collected piece would meet the necessary criteria.
The mission, which began in August, was initially expected to take two weeks for a round trip but faced multiple delays. The first delay was due to a procedural error, halting progress for nearly three weeks. Subsequently, the robot’s two cameras, designed to transmit visuals of target areas back to operators, failed, necessitating a complete extraction of the robot for repairs before the mission could be resumed on Monday.
The Context of the Mission
The Fukushima Daiichi plant lost its primary cooling system during the catastrophic earthquake and tsunami in 2011, resulting in three reactors melting down. An estimated 880 tons of hazardous radioactive melted fuel is believed to remain within the facility, prompting TEPCO to deploy various robotic investigations to determine how to safely decommission the plant.
On Wednesday, Telisco successfully cut the piece of melted fuel, estimated to weigh less than 3 grams (0.1 ounces), from a location directly beneath the Unit 2 reactor core, where a large quantity of melted fuel had fallen thirteen years prior.
Plant chief Akira Ono emphasized that the retrieval of even a small piece of fuel is critical for planning the decommissioning strategy, developing necessary technologies and robots, and gaining retrospective insights into the accident’s causes.
Challenges Ahead
The government and TEPCO have set a decommissioning timeline of 30 to 40 years, a target that experts consider overly optimistic and in need of revision. Currently, there is no definitive plan in place for the complete removal or final disposal of the fuel debris.
As recovery efforts continue, the advancements made with Telisco offer a glimmer of hope in the daunting task of decommissioning the Fukushima Daiichi plant and addressing the long-term effects of the disaster.
