Energy Department says advanced nuclear reactor first to reach critical milestone

By — Matthew Daly, Associated Press Matthew Daly, Associated Press Leave your feedback Share Copy URL https://www.pbs.org/newshour/nation/energy-department-says-advanced-nuclear-reactor-first-to-reach-critical-milestone Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter Energy Department says advanced nuclear reactor first to reach critical milestone Nation Jun 5, 2026 5:48 PM EDT WASHINGTON (AP) — The Energy Department says a small nuclear reactor under development at a national lab has reached a crucial milestone that could allow it to produce electricity within a few years. The microreactor being developed by Antares Nuclear Inc. at the Idaho National Lab reached "criticality" on Thursday, Energy Secretary Chris Wright said. The milestone occurs when a nuclear reactor achieves a self-sustaining chain reaction capable of producing a steady release of energy. WATCH: Trump signs executive orders to speed development of U.S. nuclear power Antares is the first private company to bring an advanced reactor to criticality under a pilot program begun last year by the Trump administration meant to supercharge nuclear energy production in the U.S. The demonstration was conducted in partnership with the Energy Department and other contractors with support from the U.S. Army. Grow your mind Subscribe to our Science Newsletter to explore the wide worlds of science, health and technology. "We are very excited by this news today," Wright said Friday on a call with reporters. "I think June 4th will be a historic day in the American nuclear renaissance." Antares and its partners "have shown America can do bold things," Wright added. "America has great technology, great entrepreneurs that are ready to drive energy innovation to power our future, lower energy costs and make our country more powerful." Trump administration pushing to ramp up nuclear power The achievement shows that the Trump administration's push to remove regulatory barriers is helping to advance new nuclear technologies, Wright said. President Donald Trump signed executive orders in May 2025 intended to speed up the development of nuclear power, including steps that grant Wright authority to approve some advanced reactor designs and projects. Trump's orders limit some authority of the Nuclear Regulatory Commission, the independent safety agency that has regulated the U.S. nuclear industry for five decades. Skeptics warn that nuclear energy poses risks and say microreactors may not be safe or feasible and have not proved they can meet demand for a reasonable price. While the Antares system is years away from commercial use, achieving criticality is a notable step. The California-based company, which is initially targeting military applications, said it expects to begin producing electricity by late 2027 and see its systems deployed in the field by the end of 2028, CEO Jordan Bramble said Friday. "Nuclear in America has been defined for too long by delays, by compa