The first small modular nuclear reactor in the Trump administration’s pilot program to develop advanced nuclear energy has hit a crucial milestone toward deploying more nuclear power across the country. The Department of Energy announced that an advanced reactor being developed by Antares Nuclear under the agency’s Reactor Pilot Program achieved criticality. Reaching criticality means that a reactor is perfectly stable and its nuclear chain reaction is self-sustaining and able to produce energy.
The administration said that Antares’ design, known as Mark-0, successfully completed a zero-power fueled demonstration at the Energy Department’s Idaho National Laboratory. The agency said the test confirmed that the reactor can operate safely, creating a pathway for similar reactors to produce electricity as soon as 2027.
“It is fitting that on the eve of our nation’s 250th anniversary, we are witnessing a historic moment for American energy,” Energy Secretary Chris Wright said in a statement. “For the first time in more than four decades, a new privately developed non-light-water reactor has reached criticality in the United States.”
The Mark-0 is the first of several advanced reactors that is expected to reach criticality by July 4. This deadline was set by President Donald Trump last year in a series of executive orders aimed at boosting nuclear energy deployment and quadrupling domestic capacity by 2050.
