The test also marks a notable first for the Department of Energy’s Reactor Pilot Program. Ward 250 became the first reactor authorized under the program to reach criticality outside a national laboratory, highlighting the government’s effort to accelerate commercial reactor development. Federal officials described the milestone as another sign that advanced nuclear projects are moving from concept to reality at a faster pace than in previous decades.

Racing toward deployment

The Ward 250 reactor is the second advanced reactor expected to reach criticality under goals established by President Donald Trump’s May 2025 executive order. The order called for multiple advanced reactor demonstrations to achieve criticality before July 4, 2026. Earlier this month, Antares Nuclear reached the same milestone with its Mark-0 reactor at Idaho National Laboratory. Together, the projects represent some of the fastest-moving reactor demonstrations currently underway in the United States.

Energy Secretary Chris Wright said the achievement reflects growing momentum across the domestic nuclear sector. “Today marks another historic moment for America’s nuclear renaissance,” Wright said.

He pointed to several recent accomplishments, including the first airlift of a small reactor aboard a U.S. military C-17 aircraft. Wright said such milestones demonstrate how quickly advanced nuclear technologies are progressing under current federal initiatives.

Built in nine months

Valar Atomics completed the reactor project in less than a year. According to founder and CEO Isaiah Taylor, the site was empty nine months ago. “Today, there’s a critical reactor on it, built and operated by the Valar team,” Taylor said.

The company developed Ward 250 as a power-producing reactor rather than a laboratory experiment. Achieving criticality confirms that the design can sustain the nuclear reactions required for future energy production.

Taylor credited support from the Department of Energy, Utah state officials, local communities, and project partners for helping the company meet its development goals.

New path for reactors

The Department of Energy launched the Reactor Pilot Program to shorten development timelines for first-of-a-kind advanced reactors. The initiative uses existing DOE authority to authorize reactor demonstrations while developers continue working toward commercial licensing pathways.

Officials view the program as a way to reduce barriers that have historically slowed nuclear innovation in the United States. Building on the program’s early progress, the Department recently introduced the Nuclear Energy Launch Pad. The effort aims to further accelerate testing, validation, and deployment of advanced reactor technologies.

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