Cooling equipment at the Palo Verde Nuclear Power Plant.
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VC investment in nuclear fission startups set records in 2025 as investors look to new energy sources to bolster the grid, according to PitchBook’s latest analyst note.
As energy demand has accelerated across the US and hyperscalers have inked deals for new data center projects, investors have come to embrace nuclear energy. The investor interest is also notable for the broader climate tech sector, which has had a tumultuous couple of years.
The rising demand for adaptable energy technologies pushed up valuations in nuclear fission. The median pre-money valuation jumped from $36.9 million to $106 million in 2025 as the segment recorded its best year yet for total deals and capital raised.
A handful of investors are especially bullish: specialist VC Nucleation Capital has made a total of 14 bets in the last 5 years, with French CVC CEA Investissement not far behind.
Nuclear fission is a broad category of companies that facilitate the generation of renewable nuclear energy.
Much of the venture capital now flowing into fission is going into small modular reactor technology, with two prominent examples being X-energy‘s $700 million Series D in November and Last Energy’s $100 million Series C in December.
Small modular reactors, in particular, are proving especially popular for their adaptability and scalability to multiple projects. And compared to other renewable next-generation energy sources, SMRs have relatively short timelines to commercialization—experts expect modular reactors could be operational by the early 2030s.
Radiant Nuclear, for example, has said it aims to scale to building 50 small reactors annually within a few years of beginning production in 2028. A producer of portable nuclear microreactors, Radiant raised two rounds of capital in 2025 totaling $465 million to scale to that production target.
A growing political appetite for the technology also helps. The Department of Energy has made several investments in small modular reactors and the supply chain for low-enriched uranium.
Investors in nuclear fusion, by contrast, are staring down the barrel of 15+ years for getting commercial-scale power plants up and running, and there are significant scientific breakthroughs to achieve first.
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