Trial lifting of damaged fuel assembly completed at Unit 2 of Japan's Fukushima Daiichi Nuclear Power Station

Tokyo Electric Power Company (TEPCO) announced on August 18 that a trial lifting of a damaged fuel assembly in the spent fuel pool of Unit 2 at the Fukushima Daiichi Nuclear Power Station has been completed. The assembly was damaged in a fall 45 years ago and was subsequently repaired with wire. This trial lifting was conducted to confirm whether it can be safely handled during the subsequent removal operation.

A total of 615 fuel assemblies are stored in the Unit 2 fuel pool, including 587 spent fuel assemblies and 28 unused fuel assemblies. The removal work began on June 2, and the fuel assemblies will be transferred to the shared fuel pool within the plant site. As of August 17, 35 fuel assemblies had been removed. Despite interruptions during the operation, Tokyo Electric Power Company still plans to complete the removal of all nuclear fuel from the Unit 2 fuel pool by the end of fiscal year 2028.

The fuel assembly subject to this trial lifting is one of the "non-intact fuel" assemblies in the Unit 2 fuel pool. The assembly was damaged in a fall in 1981 and could not be lifted at the time; it was restored to a liftable condition the following year after being repaired with wire. Following the 2011 Fukushima Daiichi accident, seawater was injected into the Unit 2 fuel pool. To confirm that the repair wire still possesses sufficient strength under similar conditions, Tokyo Electric Power Company previously conducted corrosion tests using wire of similar shape.

According to Tokyo Electric Power Company, the trial lifting on August 18 began at approximately 1:50 p.m., during which it was confirmed that the fuel assembly could be raised by approximately 15 centimeters, and the test concluded at approximately 2:30 p.m. The assembly is planned to be the 615th and final fuel assembly to be removed from the Unit 2 fuel pool.

In addition to this assembly, two other fuel assemblies classified as non-intact are stored in the Unit 2 fuel pool. One of them has a pinhole-sized hole in the cladding tube and is a leaking fuel assembly confirmed before the earthquake; the other has partial deformation of components. Tokyo Electric Power Company stated that these two fuel assemblies differ from the one subject to this trial lifting and can be handled with fuel handling equipment in the same manner as ordinary fuel assemblies.

Meanwhile, preparations for the third trial removal of fuel debris from Unit 2 at the Fukushima Daiichi Nuclear Power Station are still underway. Unit 2 conducted fuel debris removal trials in November 2024 and April 2025, with a total of approximately 0.9 grams retrieved across the two operations—less than the weight of a single 1-yen coin. The third trial was previously planned to begin in July 2026, but due to malfunctions in some robotic equipment, the original plan has been cancelled and the subsequent schedule will be reassessed.

Current estimates indicate that approximately 880 tons of fuel debris and other residual materials remain at the Fukushima Daiichi Nuclear Power Station, with the amount retrieved so far accounting for only an extremely small fraction. In addition to the retrieval of melted nuclear fuel, the removal of spent fuel from the fuel pools of each unit and its stable storage is also a key task in the decommissioning project. The Japanese government and Tokyo Electric Power Company have set a target of completing the decommissioning of the Fukushima Daiichi Nuclear Power Station by 2051; TEPCO also plans to complete the removal of fuel from the fuel pools of all six units by 2031.