Pilot reactor at Texas A&M's RELLIS campus clears its last federal safety analysis before a startup review

The nuclear reactor being built at Texas A&M's RELLIS campus in Bryan has cleared the last safety analysis in the U.S. Department of Energy's approval process, its developer said this week.

Last Energy, a company developing small nuclear plants, said in an announcement from Austin on Monday that DOE had approved the Documented Safety Analysis for its pilot reactor at Texas A&M-RELLIS. The company describes that document as "the final and most comprehensive safety analysis" in the department's process.

It lays out how the reactor and the facility around it will be run safely, and it builds on a preliminary analysis that DOE approved in May.

With that approval in hand, the project moves to a DOE readiness review. That review is the last step before the department can authorize the reactor to reach criticality and begin operating, according to the company. The announcement did not give a timeline for the review or for startup.

What is being built

Last Energy and Texas A&M agreed in October 2025 to build a 5-megawatt microreactor at RELLIS, a pilot known as the PWR-5, Interesting Engineering reported.

The company says the pilot uses the same full-size reactor core as its commercial design, the PWR-20, a 20-megawatt plant meant to be built in a factory, shipped by road and assembled on site to sell round-the-clock power to data centers and industrial users.

The reactor is a pressurized water design fueled with ordinary low-enriched uranium, an established technology. Last Energy says its main innovation is the containment: a 1,000-ton sealed steel structure that holds the primary systems and is built to run without workers going inside.

A federal shortcut for test reactors

The RELLIS project is in DOE's Reactor Pilot Program, which picked Last Energy in August 2025. An executive order from President Donald Trump set up the program to speed reactor demonstrations by authorizing test reactors through the Energy Department's own process.

That route covers only the demonstration unit. Any commercial plant the company builds later would still need approval from the Nuclear Regulatory Commission, Interesting Engineering noted.

Sources

lastenergy.com

interestingengineering.com