Why are new nuclear plants so expensive and so late?

New nuclear plants are expensive and slow because almost all of the cost comes before the first unit of electricity is sold. Building one needs a very large upfront investment, while fuel, operations and maintenance are relatively small parts of the total. A plant earns nothing while it is being built, and interest accrues on the debt from the day it is borrowed, so every year of delay adds finance charges.

The recent record in Europe and the United States shows how that plays out. Flamanville 3 in France began construction in 2007, with EDF estimating 3.3 billion euros and 54 months of building. In July 2020 the French Cour des Comptes put the total cost at up to 19.1 billion euros, and the reactor was connected to the grid on 21 December 2024. Vogtle units 3 and 4 in Georgia were originally certified at 14 billion dollars, and by 2023 costs had risen to 34 billion dollars. Hinkley Point C in England was expected to finish in 2025 and, as of 2026, Unit 1 is projected for 2030.

It does not have to go this way everywhere. Rapid cost increases came in the 1970s, especially in the United States, while Japan and Korea have had periods of stable and falling construction costs. Supporters add that carbon pricing favours nuclear against fossil fuels. Critics, citing a 2019 DIW Berlin study, say nuclear has not been profitable anywhere in the world, though a follow-up study from a pro-nuclear society disputed that.