Apollo Atomics founders Assil Halimi (l) and Drew Walker
MIT spinoff Apollo Atomics, which is building compact pressurized water reactors (PWRs) with high power density, has announced the closing of a $31 million seed funding round led by San Francisco venture firm FCVC.
Other backers of the Cambridge, Mass., firm includeY Combinator, Telesoft Partners, Alumni Ventures, Robinhood Ventures, Nucleation Capital, Pelion VC, and Duke Capital Partners. Notable individual investors included former CoreWeave executive Evan Meagher, Y Combinator founder Paul Graham, Starcloud founder Philip Johnston, Eight Sleep CEO Matteo Franceschetti and RedSeal CEO Ray Rothrock.
Apollo Atomics was founded in 2024 by CEO Assil Halimi, who received a PhD in Nuclear Science and Engineering, andDrew Walker, an entrepreneur who once led operations and events at the White House. Apollo aims to commercialize a nuclear platform designed to be manufactured at scale. The Y Combinator-backed company said it will use the capital to expand demonstration and long-duration reliability testing, build manufacturing capacity and advance its regulatory work with the U.S. Nuclear Regulatory Commission (NRC).
“Apollo Atomics is the only nuclear company that can deliver high power output nuclear reactors (>80 MW) on a truck,” Halimi said in a LinkedIn post. “The higher power density is the strongest argument for cost effectiveness and mass manufacturing in the nuclear industry today. We achieve this without relying on exotic/scarce fuel, unqualified materials, or high regulatory uncertainty.”
At the center of Apollo’s innovation is a redesigned steam generator, believed to be the largest and most complex component in the nuclear steam system. Its steam system is designed to deliver far higher power density than conventional designs, and it is so compact as to be transported by truck. Apollo says that advancement can reduce the overall reactor footprint by roughly 40 times. Its working reactor-system demonstrator was developed within MIT’s Department of Nuclear Science and Engineering and validated for its hardware under prototypic commercial reactor conditions.
Apollo is developing three reactor systems —a 10-megawatt electric A-10, a 50-megawatt A-50 and a 300-megawatt A-300. Each of them can serve data centers, industrial facilities, utilities and other large energy users. Apollo said it has more than 20 gigawatts of signed letters of intent in its commercial pipeline.
