advanced-nuclear
(2)
Apollo Atomics
Apollo Atomics is a Cambridge, Massachusetts nuclear startup building the most power-dense pressurized water reactor. By redesigning the steam generator - the bulkiest part of a conventional plant - into a proprietary Compact Steam Generator, the company shrinks a proven reactor design by roughly an order of magnitude, turning a decade-long construction project into a factory-built machine that fits on a truck and deploys in under 24 months. Founded by MIT nuclear PhD Assil Halimi and operator Drew Walker, Apollo is in Y Combinator's Spring 2026 batch and is testing its design in collaboration with MIT.
The Nuclear Company
The Nuclear Company is a U.S. nuclear infrastructure platform building a standardized fleet of large reactors using proven, already-licensed designs. Rather than inventing new reactor technology, it applies a 'design-once, build-many' methodology layered with AI and digital-twin software to cut the cost and timeline of building gigawatt-scale nuclear power. Founded in 2023 by Jonathan Webb, Kiran Bhatraju, and Patrick Maloney, it has raised about $70M to evaluate sites for an initial 6-gigawatt fleet targeted for the early 2030s.