Fessenheim, a nuclear power plant in northeastern France, has transitioned from an energy production site to a major construction and decommissioning project. The plant’s two reactors were shut down in February and June 2020 after operating for 43 years. The decommissioning process, which began in 2020, is expected to take over two decades and will not be fully completed until 2048. This project involves handling around 405,000 tonnes of materials, with 95 percent of these materials being non-radioactive and reusable on-site. The remaining 5 percent—about 20,000 tonnes—will require specialized handling based on their level of radioactivity. The decision to shut down the reactors was made under a protocol signed in September 2019 between the French government and EDF, the state-owned electricity company. The government agreed to compensate EDF for the early closure with a payment of around 400 million euros over four years. This compensation covered the costs of decommissioning, post-operation expenses, and staff retraining. The decommissioning process includes removing 99.9 percent of the radioactivity from the site, with used nuclear fuel being transported to the Orano recycling plant in La Hague, a task completed by the summer of 2022. Sorted radioactive waste will be stored temporarily in the former machine room, which has been modified for this purpose by removing its turbines. From there, the waste will be sent to the National Agency for the Management of Radioactive Waste in the Aube, a facility dedicated to handling such materials safely. Johann Maisonneuve, head of the decommissioning project, noted that the two reactors at Fessenheim are the first modern reactors to be decommissioned in France, unlike earlier efforts on older reactor prototypes such as Chooz A. The decommissioning decree, signed in May 2026, officially sets the completion date for the project no later than 2048. The decommissioning project will employ between 300 and 400 people annually and is expected to cost around 700 million euros per reactor. Already, 30 million euros worth of equipment from Fessenheim has been reused at other nuclear sites across France, including turbines now helping to generate electricity at Dampierre in the Loiret and Gravelines in the Nord. EDF plans to build a technocenter next to the Fessenheim site to recycle metals with very low levels of radioactivity from decommissioned nuclear plants. The goal is to reduce the time required for similar projects to 15 years and lower the cost to 500 million euros per reactor. EDF is now looking to apply these lessons to international markets, as many reactors in Europe and the United States will require decommissioning in the coming decades. Fessenheim is being treated as a full-scale test site for these future efforts.