The Flamanville EPR reactor, a nuclear power plant in France, was first announced in 2007 with a budget of 3.4 billion euros and an expected start-up by 2012. However, the project has experienced significant cost increases over the years. According to the Court of Audit, the total cost of the project now stands at 23.7 billion euros when adjusted for 2023 prices, or 20.4 billion euros in 2015 prices. This is more than seven times the original budget. The reactor finally connected to the national electricity grid on December 21, 2024, over a decade after the initially planned commissioning date. From the beginning, the project encountered numerous technical and logistical challenges. These included problems with civil engineering, difficulties in qualifying equipment for use in a nuclear environment, and concerns about the safety of materials, particularly the steel used in the reactor vessel. These issues caused repeated delays and rising costs. In 2015, EDF, the French energy company managing the project, revised the cost estimate to 10.5 billion euros and pushed back the commissioning date to the fourth quarter of 2018, which was not achieved. In January 2025, the Court of Audit released a new report that recalculated the project's total cost. The increase was attributed to changes in how financial provisions were calculated, the cost of funding the project, and additional expenses related to testing, the initial phase of operation, and the preparation for the reactor’s first shutdown in 2026. These factors led to an increase of nearly 1.5 billion euros compared to previous estimates. EDF itself estimates the project's total cost at 19.3 billion euros in 2015 prices or 22.6 billion euros in 2023 prices, which is about one billion euros less than the Court of Audit’s calculation. The Court has also raised concerns about the reactor’s future profitability, noting that to achieve a 4 percent profitability, each megawatt-hour of electricity produced would need to be sold for 122 euros, and 176 euros for a 7 percent profitability. These figures highlight the high costs and economic risks involved in the project. The EPR2 program, which includes plans for six new reactors similar to Flamanville, also faces similar financial risks. The Court of Audit reported a 30 percent increase in the construction budget for these reactors, rising from 51.7 billion euros to 67.4 billion euros, under the same economic conditions and excluding inflation. This underscores the ongoing challenges in building and maintaining new nuclear power plants in France.