Santa Clara, California-based Oklo's Groves Isotope Test Reactor reached criticality on Aug. 5 at the company's plant in Lockhart, Texas, and will produce isotopes for medicine, advanced manufacturing, scientific research, space exploration, and national security needs.

Unlike massive cement-siloed, utility-scale reactors such as the Westinghouse AP1000, the Groves reactor is a circular 22.5-foot-diameter nuclear generator that can be shipped by truck or rail and planted in a 35-foot-deep reinforced concrete cavity, making it a distinct entry in an expanding range of small, portable reactors on the cusp of being retail ready.

As John Haughey details for The Epoch Times, Oklo is one of 10 companies selected by the Department of Energy (DOE) in August 2025 to develop 11 "first mover" innovations under a reactor pilot program authorized by President Donald Trump in four May 2025 "Nuclear Renaissance" executive orders that call for licensing 10 new reactors by 2030 and quadrupling the nation's nuclear energy capacity by 2050.

The president's executive orders included incentives for three prototypes to reach "criticality" by July 4 to commemorate the 250th anniversary of the nation's founding. That goal was eclipsed when Aalo Atomics' Aalo-X became the fourth small reactor to attain criticality on July 4 after Antares Nuclear's Mark-0 on June 4 became the first new reactor type in the United States to achieve the status since 1973.

With Oklo's Groves reactor becoming the fifth to reach criticality in the last two months, Trump's five-year goal for 10 small reactor types to be validated is already halfway accomplished. Energy Secretary Chris Wright said as many as seven would achieve criticality by year's end.

The Groves reactor is one of two Oklo reactor developments that qualified for the pilot program. The company is also building a 75 megawatt reactor to anchor its Aurora Powerhouse Project at Idaho National Laboratory's Materials and Fuels Complex, a prototype the company anticipates will be ready for "commercial operations" by 2028.

The Groves reactor is also one of two that attained viability in a privately owned plant rather than on the 890-square-mile Idaho National Lab near Idaho Falls.

"Thanks to President Trump's precedent-setting directive to create the Reactor Pilot Program, Oklo's Groves Isotope Test Reactor is part of the revival of America's nuclear energy industry," Assistant Secretary for Nuclear Energy Ted Garrish said in a statement. "We applaud the work of the Oklo, DOE, and Idaho National Laboratory staff who helped achieve this milestone."