Texas reactor reached criticality in a year, aiming to produce medical isotopes

Representative Image of a modern Texas nuclear reactor supporting advanced isotope production for healthcare (AI-generated image) Every day, more than 40,000 Americans undergo a diagnostic scan that depends on technetium-99m, a radioactive isotope used to image the heart, spot cancer and check kidney function. Every milligram of the molybdenum-99 that produces it currently arrives in the United States from aging foreign reactors, since the country has no domestic supply of its own. On the evening of August 5, 2026, that changed in a small way. In Lockhart, Texas, just south of Austin, Oklo Inc. announced that its Groves Isotope Test Reactor achieved first criticality, meaning it sustained a controlled nuclear chain reaction on its own for the first time. The reactor was not built to generate electricity. It exists purely to prove that the United States can finally produce its own supply of critical medical isotopes, on a timeline that once seemed impossible for the domestic nuclear industry. If this pace can be replicated at commercial scale, it could mark a genuine turning point for American healthcare infrastructure, finally freeing hospitals from dependence on aging foreign reac...