- Apollo Atomics has received $31 million in seed funding, with FCVC leading, to develop nuclear reactors that can be built in factories.
- Its new steam generator design makes the reactor approximately 40 times smaller.
- The company’s advantage might stem from the regulatory expertise of one of its co-founders, rather than merely from technical innovation.
Apollo Atomics, a nuclear startup founded in 2025 by Assil Halimi and Drew Walker, raised $31 million on the basis that policy expertise is just as important as scientific ability when it comes to obtaining reactor licences.
FCVC led the seed financing round for the Cambridge, Massachusetts-based company, raising $26 million in equity and $5 million in debt.
Other investors in the round were Y Combinator, Telesoft Partners, Alumni Ventures, Robinhood Ventures, Nucleation Capital, Pelion VC, Duke Capital Partners, as well as Paul Graham, Philip Johnston, Matteo Franceschetti, and Ray Rothrock.
Same physics, smaller design
Apollo uses the standard pressurised-water design common to most nuclear power plants, but it has redesigned the steam generator, normally the largest and most complex part.
The new steam generator has about ten times the power density, a feature which the company states makes the reactor about 40 times smaller. This reduced size allows it to be built in a factory, transported to the site, and brought into operation within two years.
By securing supply chains for pressurised water reactors, the company can avoid the technological risks its competitors encounter when developing new reactor chemistries. The company intends to differentiate itself by speeding up manufacturing and regulatory approval, not by altering the reactor physics.
Apollo has constructed and run a reactor-system demonstrator at MIT’s Department of Nuclear Science and Engineering. The company states that the fuel configuration of its commercial reactor has achieved full-power criticality. It has entered into letters of intent for more than twenty gigawatts for its intended products, comprising the 10-megawatt A-10, the 50-megawatt A-50, and the 300-megawatt A-300.
A crowded field, where paperwork matters as much as physics
This year, funding for nuclear projects has increased, and Apollo is now entering a highly active sector.
Valar Atomics recently completed a $1 billion Series B round, bringing its valuation to $6 billion. Antares has raised $470 million in order to meet a deadline set by the Pentagon.
Radiant Nuclear obtained $300 million just one day after Last Energy closed its $100 million funding round. Blue Energy also raised $380 million for the same factory-built method, although its approach involves financing entire plants rather than redesigning the reactor core.
Oklo, chaired by Sam Altman, has secured a 12-gigawatt supply agreement with Switch but is still awaiting full design approval from the Nuclear Regulatory Commission. Kairos Power has received the first construction permit from the NRC for a non-water-cooled reactor in more than fifty years and also has a 500-megawatt deal with Google.
These companies do not currently hold a full commercial licence, and Apollo intends to address this. Christopher Hanson, who was previously chairman of the NRC, serves on Apollo’s advisory board, and the company has submitted a plan aiming to obtain NRC approval of its fuel design by the end of 2026.
Apollo is relying on Walker’s expertise in logistics and manufacturing to accelerate the regulatory process, rather than on reactor physics. However, it is not clear that this advantage will be sufficient, as the NRC has delayed companies with more resources and greater progress than Apollo.
What comes next
The funds obtained will assist Apollo in constructing its next demonstrator, the one-megawatt A-1, and will also enable long-term reliability testing, the scaling of manufacturing, and further work with the NRC. Testing the new steam generator design should be straightforward.
The market for small modular reactors is projected to increase from $6.54 billion in 2025 to $10.69 billion by 2033, representing an annual growth rate of 6.8%. Investment in nuclear energy is being driven by the growing demand for power in data centres, which is outpacing the electrical grids’ ability to meet it.
The key issue is whether a former White House operator can navigate regulatory obstacles more effectively than the teams at Oklo and Kairos, who are led by physicists.
