Small Modular Reactors Startups funded by Y Combinator (YC) 2026

About Oklo Inc.: Oklo Inc. (Oklo) is developing advanced fission power plants to provide emission-free, reliable, and affordable energy. Oklo received a Site Use Permit from the U.S Department of Energy, has performed successful prototypic fuel fabrication, was awarded fuel material from Idaho National Laboratory, developed the first advanced fission combined license application accepted and docketed by the U.S. Nuclear Regulatory Commission, and is developing advanced fuel recycling technologies in collaboration with the U.S. Department of Energy and national laboratories. Oklo has been featured in Time, Newsweek, Wall Street Journal, CNBC, Popular Mechanics, Wired, Architectural Digest, Hyperallergic, POWER Magazine, has been the subject of a Harvard Business School case, and is featured in the Oliver Stone documentary Nuclear, among other features.

Atomic Alchemy is building a bank of reactors to produce the nuclear material that goes into nuclear medicine. Radiopharmaceuticals are vitally important in biological tracers, diagnostic imaging, and cancer treatments. Currently, the world's supply of Molybdenum-99, the cornerstone of 80% of all nuclear medicine procedures, is sourced from just six government-run, scientific research reactors abroad. Five of these reactors are 45-65 years old and are quickly coming to the end of their operational life. This has cultivated a fragile and lengthy supply chain, at odds with the nature of radioactive material. This issue and its implications do not just effect molybdenum, but any other reactor-based isotope. Many promising cancer therapies are stuck in clinical trials, unable to secure enough material in a timely manner. Research doesn’t even happen because of the difficulty of sourcing any new isotopes. It doesn't have to be this way. Atomic Alchemy is working to solve this by building the world's first scalable radioisotope production facility. This facility will contain the world’s first privately-owned nuclear reactors dedicated to radioisotope production.