Apollo Atomics is developing a compact nuclear reactor system built around a radically miniaturized steam generator, the component that produces steam from a reactor's coolant loop to drive a turbine. Where conventional steam generators are hand-built and several stories tall, Apollo's design threads coolant and water through a compact metal block laced with needle-thin channels, shrinking the whole reactor system roughly 40-fold versus a conventional design. The company has built a 40-kilowatt demonstration reactor at MIT, plans three commercial reactor sizes from 10 to 300 megawatts-electric, and targets 3 cents per kilowatt-hour electricity with commercial deployment in 2028. Apollo was part of Y Combinator's Spring 2026 batch.
FCVC (lead); Telesoft Partners, Y Combinator, Alumni Ventures, Robinhood Ventures, Nucleation Capital, Pelion VC, Duke Capital Partners, New Era Ventures, Orange Collective, Stanford University, E14 Fund, Neutron Power Ventures (participating)