All 1,535 Fuel Assemblies Removed from Unit 4 Spent Fuel Pool

On December 22, 2014, TEPCO completed the removal of all 1,535 fuel assemblies from Unit 4's spent fuel pool — the first major fuel removal milestone. The operation, conducted in a custom-built cover structure, transferred the assemblies to the site's common spent fuel pool. This was the most urgent task in the early decommissioning roadmap, as Unit 4's elevated spent fuel pool had been a source of catastrophic concern in the weeks after the accident. The successful completion was widely hailed as an engineering achievement accomplished ahead of schedule.