The EPR reactor at Flamanville, France, has officially begun operating and is now undergoing a major inspection that is expected to last one year. This reactor, known as a third-generation European Pressurized Reactor (EPR), is the latest addition to France’s nuclear power plants. Such inspections are required by regulatory standards and must occur within 30 months of the first fuel loading. The current inspection involves replacing the reactor vessel head and conducting a detailed check of the entire facility. The process is expected to cost several hundred million euros and includes over 20,000 activities, requiring the coordination of around 2,500 people and 200 partner companies from EDF's industrial network. According to Renaud Crassous, deputy director of performance for EDF's nuclear production division, three major inspections will be carried out during this “comprehensive inspection number 1.” These include examining the primary circuit vessel, which collects heat from the nuclear reaction, and checking the tightness of the hydraulic circuits. The replacement of the EPR vessel head, manufactured by Framatome in Saint-Marcel, is necessary due to known long-standing issues. This head is a crucial component of the reactor, weighing nearly 100 tons and over 5 meters in diameter, and houses mechanisms for controlling the control rod clusters. Other tasks will involve modifying equipment such as cooling heat exchangers, control systems, and the power plant control room. Crassous compared the scale of the inspection to a decade-long process typically carried out on older reactors that have been in operation for 30 or 40 years. He noted that the number of activities involved is similar to those required for the decade-long inspection of Paluel 1, a reactor in Seine-Maritime that recently celebrated its 40th anniversary and was recently reconnected to the grid. The comprehensive inspection at Flamanville will take longer than those of other plants, such as Chooz or Civaux, which typically last 190 to 200 days, due to the extensive nature of the inspection. The first phase of the reactor's operation has confirmed that the facility is performing well and has identified areas for improvement. The Flamanville EPR has already produced 9.9 terawatt-hours (TWh) of electricity and reached 100% of its power capacity on December 14, 2025. In 2026 alone, it exceeded its production targets. The reactor has a net electrical power of 1,600 megawatts, which is the amount of electricity injected into the national grid. Flamanville 3 is the first nuclear reactor to start operating in France in 25 years. It was connected to the grid at the end of 2024, 12 years late compared to the original schedule. Its costs have also surged, increasing from an initial estimate of 3.3 billion euros to around 23.7 billion euros as of 2023, according to the Court of Audit. Located near the English Channel alongside two other reactors, Flamanville 3 is the most powerful reactor in the French nuclear fleet.