The Tentative First Steps To Removing Fukushima’s Nuclear Fuel Has Begun

Decommissioning teams at Japan’s Fukushima nuclear plant have begun a two-week operation aimed at retrieving a sample of the radioactive debris that remains inside the facility’s stricken nuclear reactors, using a telescoping robot custom-built for the task, thirteen years after the power plant suffered multiple meltdowns in the wake of the tsunami that devastated the Japanese coast on March 11, 2011.

Originally scheduled to begin on August 22, the effort to retrieve a sample of melted fuel from the Fukushima Daiichi nuclear plant had to be delayed due to five of the pipes that are to be used to retrieve material being assembled in the wrong order. The remote-controlled robot being used for the task, built by Mitsubishi Heavy Industries, is capable of extending a telescoping arm up to 22 meters (72 feet), with the goal of collecting a 3-gram (0.1 ounce) sample of corium, a highly radioactive alloy formed from the runaway mixing of melted nuclear fuel, fission byproducts and the reactor’s fuel casings and control rods.

The overall operation was due to start two years ago in Fukushima’s Unit 2 reactor, but the project was plagued by numerous setbacks, most notably the engineering challenge of building robots that can withstand intensely radioactive environment such as the ones found in Fukushima’s reactors.

In February 2024, two mini-drones were sent into the reactor to map out a path for the sample-collecting robot to take; the drones were accompanied by a snake-like robot that used a wireless relay to boost the signals being transmitted to and from the drones, cutting through the reactor’s disruptive radiation.

This operation is intended to pave the way for the eventual removal of all of the fuel from the three reactors that suffered meltdown as a result of the disaster, although the removal of the 880 tons of highly radioactive material is expected to take a number of decades to complete.

“We believe the upcoming test removal of fuel debris from Unit 2 is an extremely important step to steadily carry out future decommissioning work,” according to Yusuke Nakagawa, a TEPCO group manager for the fuel debris retrieval program. “It is important to proceed with the test removal safely and steadily.”

A great deal of controversy occurred last year when the Tokyo Electric Power Company (TEPCO) began releasing the 1.34 million tonnes of treated seawater that had been used to cool the reactors over the 12 years since the meltdown into the ocean; although the water had been scrubbed of the majority of radioactive material, traces of tritium were still present in the water. Although the amount of tritium remaining in the stored water was only a fraction of the safe limits set by the World Health Organization, environmental groups and neighboring governments were critical of TEPCO’s plans.