Four companies have met the July 4, 2026, deadline that President Trump set for advanced nuclear development. Antares Nuclear, Valar Atomics, Deployable Energy, and Aalo Atomics have each achieved DOE-authorized zero-power fueled criticality—the central target of the federal Reactor Pilot Program.
The program was created in direct response to Executive Order 14301, which Trump signed on May 23, 2025, directing the Department of Energy to establish a new pathway for companies to build and test first-of-a-kind nuclear technologies. The order set an explicit goal: four reactors reaching criticality within roughly 14 months.
That benchmark has now been met.
Four companies meet the RPP criticality deadline
All four milestones unfolded in rapid succession over a single month. Antares Nuclear went first, hitting zero-power fueled criticality on June 4 at Idaho National Laboratory with its Mark-0 microreactor — a sodium heat pipe–cooled, TRISO-fueled design and a forerunner to its commercial R1 reactor. Antares became the first RPP company to clear the bar. CEO Jordan Bramble has said the company is on track to deliver commercial units to customers in 2028.
Valar Atomics followed on June 18. Its Ward 250—a 100 kW helium-cooled, TRISO-fueled high-temperature gas reactor—reached criticality at Utah’s San Rafael Energy Lab, where the company had broken ground the previous September. Valar didn’t stop there. Four days later, it announced a 10-kW power output and connected that electricity to an Nvidia Spark chip, part of a broader partnership with Nvidia to develop a 30-MW nuclear-powered data center in Utah.
Deployable Energy crossed the finish line on July 1—just three days before the deadline—achieving zero-power-fueled criticality at INL with its 1-MWe Unity high-temperature gas-cooled microreactor, roughly 150 days after starting the project. The company has stated it’s working with partners in Utah and Texas on potential applications, including data centers, research facilities, and remote resource extraction. Together, the four achievements satisfy the headline goal EO 14301 set 14 months ago.
How the reactor pilot program was created and structured
Executive Order 14301, signed on May 23, 2025, instructed the DOE to establish the Reactor Pilot Program as a new authorization pathway for companies developing first-of-a-kind nuclear technologies. The order was explicit: four reactors reaching criticality by July 4, 2026.
The DOE moved fast. In August 2025, it selected 10 companies for the RPP, then expanded the initiative in March 2026 into a longer-term effort called the Nuclear Energy Launch Pad, broadening access beyond the original cohort.
Authorization under the RPP moves through four sequential milestones. A company first signs an Other Transaction Agreement with the DOE, formalizing the partnership. Next, the DOE issues a Nuclear Safety Design Agreement approval, establishing the safety and regulatory framework. Then comes the Preliminary Documented Safety Analysis, where the DOE validates the company’s safety case. Finally, DOE approval of a fully documented safety analysis lets a company begin operating. EO 14301 also created a parallel Fuel Line Pilot Program focused on fuel-related authorization—a separate track not covered here.
Status of other companies in the RPP and nuclear energy launchpad
Several other companies are close behind the four that hit the July 4 deadline. Aalo Atomics, based in Austin, Texas, officially crossed the finish line right on the target date. Its full-scale test core for the 10-MWe sodium-cooled Aalo-X achieved zero-power criticality at Idaho National Laboratory at 12:20 a.m. MT on Saturday, July 4, 2026, following a June 25 public authorization by Energy Secretary Chris Wright.
Oklo Isotopes—formerly Atomic Alchemy, acquired by Oklo in 2025—announced this week that it secured its DSA for the Groves Isotope Test Reactor, a pool-type water-cooled isotope production reactor sited in Lockhart, Texas. The company plans to achieve criticality in July 2026.
Last Energy has completed construction of its pilot project building at Texas A&M’s RELLIS campus, installed critical reactor components, and submitted its final DSA for DOE review. It expects to complete an initial criticality test this summer, pending authorization. Radiant Industries received its first tranche of HALEU fuel at INL’s DOME facility on July 1 and plans a five-phase testing program through summer 2026, targeting progression from zero-power criticality all the way to a 150-hour full-power run without operator intervention.
Other participants are at earlier stages. Deep Fission broke ground on its underground pressurized water reactor in Parsons, Kansas, in December 2025 and is targeting full-power operations in early 2027. Natura Resources is constructing a molten salt research reactor at Abilene Christian University. Oklo’s Aurora-INL project secured its PDSA in June 2026, though no deployment timeline has been announced. Terrestrial Energy, NuCube Energy, and the Oklo Pluto project are each at various earlier points in site development or authorization work.
What comes after DOE authorization: The NRC pathway to commercial deployment
Reaching criticality under DOE authorization is a significant milestone—but it’s not a commercial operating license. Every company in the RPP and Nuclear Energy Launch Pad still needs separate approval from the Nuclear Regulatory Commission before deploying reactors commercially. That regulatory runway remains substantial for all of them.
Companies are treating their RPP and Launch Pad milestones as tools to build safety cases and data packages aimed at accelerating NRC review. A proven reactor concept with real operational data is a stronger foundation for a licensing application than a design that exists only on paper.
Most companies in both programs are targeting commercial deployments before the end of the decade. Antares has cited 2028 for commercial unit delivery. Valar’s Nvidia partnership points toward a near-term commercial application, with the Utah data center project already announced. Deep Fission is targeting commercial deployment in late 2027 or early 2028.
The takeaways from the July 4 deadline are pretty straightforward. Antares Nuclear, Valar Atomics, and Deployable Energy achieved DOE-authorized zero-power fueled criticality within the timeframe EO 14301 set. Several more are weeks or months behind them in the same authorization process. For all of them, the DOE milestones are a means to an end: the longer, harder work of obtaining NRC approval and reaching commercial deployment still lies ahead.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
