The smart money in nuclear has spent the last few years betting small. Hyperscalers like Amazon and Meta keep signing deals for small modular reactors, the compact units meant to roll off a factory line cheaper and faster than anything before them, and a lot of those reactors still only exist on paper.<\/p>\n
France looked at that bet and went the other way. In a cluster of factories in eastern France, it is forging the giant guts of full-size conventional reactors right now. Four steam generators for a single unit are being built at the same time in one plant. A concrete dome 70 meters tall, about 230 feet, is rising separately on the Normandy coast. The reactor going underneath it, called the EPR2, is the most powerful reactor design in the Western world, and France has ordered six of them.<\/p>\n
None of this is a render or a 2040 roadmap. The steel is being cut, welded, and machined this year, in plants that have spent the past decade building reactor parts for Britain and are now turning that capacity toward France’s own fleet. The money is moving too. In December, EDF’s board put a price on the whole thing and signed off on the next year’s spending. The interesting part isn’t the brochure. It’s what’s physically taking shape in the workshops.<\/p>\n
A steam generator is one of the least glamorous and most enormous objects in a nuclear plant. It is the machine that takes the heat coming off the reactor core and uses it to boil water in a separate loop, making the steam that actually spins the turbine. Every EPR-class reactor needs four of them, and they are not small.<\/p>\n
The ones Framatome<\/a> built at its Saint-Marcel plant near Chalon-sur-Sa\u00f4ne for Britain’s Hinkley Point C stand 25 meters tall and weigh 510 metric tons each, around 560 U.S. tons, by the company’s own count. That is a single component the height of an eight-story building and the weight of a loaded Boeing 747, and a reactor swallows four.<\/p>\n The news is that France is now building all four for its first next-generation reactor at the same time. According to Framatome, the Saint-Marcel plant began manufacturing the fourth EPR2 steam generator in late 2025 and is now assembling the full set of four that will equip the first EPR2 reactor at Penly, on the Normandy coast. Other pieces of the primary loop are moving in parallel.<\/p>\n The plant has already preheated the nozzle shell of the first reactor vessel, and the forge at nearby Le Creusot has turned out the ingot for one of the reactor’s coolant legs.<\/p>\n Doing all four steam generators at once matters because of how long one takes. By the account of French industrial outlet L’Usine Nouvelle<\/a>, assembling a single EPR steam generator from forged shells takes roughly four years. France hasn’t run reactor parts at this volume since the 1980s, when it was bolting together its existing fleet. Running four in parallel for one reactor, with two more pairs of reactors queued behind it, is the part of the program that has to work before any of the rest does.<\/p>\n While Burgundy forges the machinery, Normandy is pouring the building that will hold it. The contractor Eiffage<\/a> has the civil engineering job for the first two EPR2 reactors at Penly, and it describes the reactor buildings plainly: each one is a dome 70 meters high and 50 meters in diameter. For scale, that is a windowless concrete cylinder taller than the Arc de Triomphe and wide enough to park a soccer field inside, built to contain a reactor and survive whatever the reactor might do.<\/p>\n The dome is one piece of a much larger site. Eiffage’s contract covers 69 separate structures for the Penly pair, including a six-floor, 15,000-square-meter operations building, and the civil works alone are valued at more than 4 billion euros. At the peak of construction, the company expects 4,000 people on site. This is the unglamorous reality of building a full-size reactor that the small modular pitch is specifically trying to avoid: years of concrete, dozens of buildings, and a workforce the size of a small town.<\/p>\n Here is where the story bends toward the kind of factory most readers know better than a nuclear forge. France’s problem isn’t designing the EPR2. It’s making the giant parts fast enough and often enough to build six reactors without the cost spiral that wrecked the last one. The fix Framatome has landed on is borrowed straight from the auto industry.<\/p>\n According to L’Usine Nouvelle, Saint-Marcel went looking for production methods at companies like Dassault Aviation and the tractor maker Claas, and adopted lean manufacturing and takt time, the assembly-line rhythm that carmakers use to pace a plant to demand. The target is to finish one steam generator every two months by running them in parallel, rather than crafting each one as a slow, bespoke job. The plant has taken roughly 300 million euros in investment to make that shift.<\/p>\n It doesn’t stop at one site. Framatome is converting its Jeumont plant in northern France, with more than 100 million euros, to sequence critical EPR2 parts the way an automotive supplier would, chasing a build rate of about 1.5 reactors’ worth of components a year.<\/p>\n In Savoie, the company is spending 87.5 million euros on a new factory to produce the iron-nickel alloys, including the Inconel that goes inside the steam generators, with output planned from late 2027. A French company applying Volkswagen and Toyota production logic to 500-ton reactor parts is either the most sensible idea in the program or a sign of how far the industry let its skills lapse. It is probably both.<\/p>\n The thing about full-size reactors is that the brochure and the build rarely match, and France knows this better than anyone. In December, EDF told its board that its preliminary estimate for the six EPR2 reactors comes to 72.8 billion euros, about 85.3 billion dollars, at 2020 values, as World Nuclear News<\/a> reported.<\/p>\n That number has only moved one direction. It started at 51.7 billion euros, climbed to 67.4 billion in 2023, and now sits where it sits, with an independent audit due in the first quarter of 2026. The board approved 2.7 billion euros to spend on the program in 2026, and a final investment decision is targeted for the end of the year.<\/p>\n The calendar has slipped along with the price. Construction was meant to start in 2027 and the first Penly reactor was supposed to feed the grid in 2035. That date is now 2038, with the rest of the units following at intervals of up to 18 months. The reason France treats these slips as routine is sitting on the Normandy coast already, a few buildings over from the EPR2 site. Flamanville 3, France’s first EPR and the direct ancestor of the EPR2, finally connected to the grid on December 21, 2024, according to EDF<\/a>.<\/p>\n It was 12 years late and cost around 13 billion euros, roughly four times the original estimate. Luc R\u00e9mont, then EDF’s chairman and CEO, called the coupling “a historical moment for the entire nuclear sector.” It was also a warning about exactly how hard this is.<\/p>\n What makes the EPR2 program worth watching from the United States is that it is a direct rebuttal to the way most of the West is now placing its nuclear bets. Across North America, the pitch is to go small and repeatable. Ontario just set a 953-tonne basemat<\/a> for the Western world’s first grid-scale small modular reactor, a 300-megawatt machine that fits on two soccer fields.<\/p>\n A Maryland company is building pebble-bed reactors<\/a> with no fuel rods, headed for a chemical plant in Texas. Even Italy is testing a next-generation reactor by building a full-size lead-cooled demonstrator<\/a> with no uranium in it. Every one of those bets points the same way: smaller, modular, factory-built.<\/p>\n France is doing the reverse on purpose. It is the most nuclear-reliant country on Earth, drawing the largest share of any national grid from its reactors, around 70 percent in a normal year from a fleet that became 57 reactors when Flamanville 3 came online.<\/p>\n Its plan to keep that going isn’t to shrink the reactor. It’s to build the biggest design in the West, six times over, and to industrialize the supply chain so the next one costs less than the last. The same Saint-Marcel plant that spent the last decade forging steam generators for Britain’s Hinkley Point C<\/a> is the proof that the capability exists. The question is whether France can run it at the pace its own numbers demand.<\/p>\n Right now the honest scorecard is split. The steam generators are real, all four of them, taking shape in a Burgundy workshop you could walk through today. The 70-meter dome is real concrete on the Normandy coast. What isn’t real yet is a finished EPR2, a signed final investment decision, or any guarantee that 72.8 billion euros stays 72.8 billion euros. France has forged the hardest parts of a reactor before.<\/p>\n Turning that into electricity is the part that took an extra 12 years last time, and the bet is that doing it like a carmaker shaves the difference.<\/p>\n","protected":false},"excerpt":{"rendered":" The smart money in nuclear has spent the last few years betting small. Hyperscalers like Amazon and Meta keep signing … <\/p>\nA 70-meter dome and 69 other buildings<\/h2>\n
Building reactors like cars<\/h2>\n
The bill, and the calendar<\/h2>\n
The opposite bet<\/h2>\n