On May 23, 2025, President Trump signed Executive Order 14301, “Reforming Nuclear Reactor Testing at the DOE,” which instructed the Department of Energy to create a Reactor Pilot Program (RPP)—a new system in which companies could pursue DOE authorization to build and test their first-of-a-kind nuclear technologies. EO 14301 set an ambitious goal for that program: three reactors achieving criticality by July 4, 2026.

El Segundo, Calif.–based start-up Valar Atomics has taken its Ward 250 test reactor critical at the Utah San Rafael Energy Lab (USREL), becoming the second company in the Department of Energy's Reactor Pilot Program to reach the milestone, and, according to the DOE, the first to do so outside a national laboratory.

The DOE celebrated the achievement in a June 18 announcement, describing it as a "zero-power fueled criticality demonstration." The news follows a similar update for Antares Nuclear's Mark-0 reactor, which the DOE said achieved criticality at Idaho National Laboratory earlier this month.

Valar's Ward250 microreactor being loaded, without fuel, onto a C-17 aircraft. (Photo: Valar Atomics)

A public-private partnership between the Departments of Defense and Energy and Valar Atomics marked a milestone over the weekend when Valar’s Ward250 microreactor was transported (without fuel) from California to Utah using three C-17 aircraft. The reactor will now trek from Hill Air Force Base to the Utah San Rafael Energy Lab (URSEL) for testing and evaluation.

A formal press conference at Hill Air Force Base included Energy Secretary Chris Wright, Undersecretary of Defense Michael Duffey, Utah Gov. Spencer Cox, and Valar Atomics CEO Isaiah Taylor.

During his remarks, Wright discussed the significance of the day, and said “a 5‑megawatt Valar Atomics nuclear reactor was just flown from L.A. to this air force base here in Utah—an incredible 5‑megawatt reactor that powers 5,000 homes, flown in the back of a plane.” The ability to transport microreactors like the Ward250 bolsters claims that the technology could be deployed to remote locations, military installations, or to support natural disaster relief missions.

Valar Atomics has announced that its Nova Core achieved zero-power criticality on November 17 at Los Alamos National Laboratory’s National Criticality Experiments Research Center (NCERC) at the Nevada National Security Site.

It has been about three months since the Department of Energy named 10 companies for its new Reactor Pilot Program, which maps out how the DOE would meet the goal announced in May by Executive Order 14301 of having three reactors achieve criticality by July 4, 2026.

At the American Nuclear Society’s Winter Conference & Expo, leaders of advanced reactor start-ups Radiant Industries, Oklo, and Valar Atomics praised the Department of Energy’s Reactor Pilot Program, in which the companies are participating. The program aims to get at least three reactors on line by July 4, 2026.

The Department of Energy has fast-tracked its selections for the Fuel Line Pilot Program. Four companies—Oklo, Terrestrial Energy, TRISO-X, and Valar Atomics—were named September 30 as “conditional selections” for a “fast-track approach to commercial licensing,” bringing the total to five. The first company conditionally chosen for a DOE-authorized fuel fabrication facility—Standard Nuclear—was named less than three weeks after the program opened to applicants in July.

El Segundo, Calif.–based reactor start-up Valar Atomics recently announced that it has broken ground on its test reactor, the Ward 250, at Utah San Rafael Energy Lab (USREL), becoming the second company participating in the Department of Energy’s Nuclear Reactor Pilot Program to do so.

The race to bring test reactors on line by July 4, 2026, got a boost today when the Department of Energy unveiled the names of 10 companies selected for the Nuclear Reactor Pilot Program—a new pathway that allows reactor authorization outside national labs.

As first outlined in one of the four executive orders on nuclear energy released by President Trump on May 23 and in the request for applications for the Reactor Pilot Program released June 18, the companies must use their own money and sites—and DOE authorization—to get reactors operating. What they won’t need is a Nuclear Regulatory Commission license.