Nuclear startups are back in fashion with small reactors and big challenges

The nuclear industry is on the verge of a renaissance. Old factories are being renovated and investors are flooding startups with cash. In the last weeks of 2025 alone, nuclear startups raised $1.1 billionlargely on investor optimism that small nuclear reactors will succeed where the industry as a whole has recently stumbled.

Traditional nuclear reactors are massive pieces of infrastructure. The newest reactors built in the United States – Vogtle 3 and 4 in Georgia – contain tens of thousands of tons of concrete, are powered by 14-foot-tall fuel assemblies and each generate more than a gigawatt of electricity. But they were also eight years late and more than $20 billion over budget.

The new generation of nuclear start-ups hope that by downsizing the reactor they can avoid both problems. Need more power? Just add more reactors. Smaller reactors, they argue, can be built using mass production techniques, and as companies produce more parts, they should improve their manufacturing, which should reduce costs.

The magnitude of this advantage is a question that experts believe still lookingbut today’s nuclear startups depend on its value being greater than zero.

But manufacturing is not easy. Just look at Tesla’s experience: the company had great difficulty profitably producing the Model 3 in large numbers – and it had the advantage of being present in the auto industry, where the United States still has significant expertise. American nuclear startups do not benefit from this advantage.

“I have a number of friends who work in the nuclear supply chain, and they can offer me five to ten materials that we just don’t produce in the United States,” Milo Wernergeneral partner of DCVC, told TechCrunch. “We have to buy them from abroad. We have forgotten how to make them.”

Werner knows a thing or two about manufacturing. Before becoming an investor, she worked at Tesla, leading the introduction of new products, and before that she did the same at FitBit, launching four factories in China for the clothing company. Today, in addition to investing at DCVC, Werner co-founded the NextGen Industry Group, which works to advance the adoption of new technologies in the manufacturing sector.

When companies of any size want to make something, they face two main challenges, Werner said. One is capital, which is often the biggest constraint since factories are not cheap. Fortunately for the nuclear industry, this should not pose a big problem. “They are flooded with capital right now,” she said.

But the nuclear industry is not immune to another challenge that all manufacturers face: the lack of human capital. “We haven’t really built an industrial facility in 40 years in the United States,” Werner said. As a result, we have lost muscle memory. “It’s like sitting on the couch watching TV for 10 years, then getting up and trying to run a marathon the next day. It’s not good.”

After decades of offshoring, the United States lacks people experienced in building and operating factories. “There are certainly people in the United States who have done this, but we don’t have the number of people we need for everyone to have a full team of seasoned makers.” She’s not just talking about machine operators, but everyone from factory supervisors to CFOs and board members.

The good news is that Werner sees many startups, nuclear and otherwise, building early versions of their products close to their technical team. “It brings the manufacturing industry closer to the United States because it allows them to experience this cycle of improvement.”

To reap the benefits of mass manufacturing, it helps for startups of all stripes to start small and scale up. “It’s very important for investors to really leverage modularity,” she said. The modular approach helps companies start producing small volumes from the beginning so they can collect data about the manufacturing process. Ideally, this data will improve over time, which can reassure investors.

The benefits of mass manufacturing don’t happen overnight. Companies often anticipate cost reductions that may result from learning through manufacturing, but this may take longer than expected. “Often it takes years, even a decade, to get there,” Werner said.