Austin, Texas-based Last Energy received the Department of Energy’s approval of its preliminary safety analysis last week for its test microreactor at the Texas A&M-RELLIS campus in Bryan, Texas.
Last Energy becomes the most recent nuclear company to achieve this regulatory milestone under DOE’s reactor pilot program, which seeks to have at least three test reactors reach criticality by July 4. The approval of the preliminary design safety analysis lays the foundation of the initial safety basis for the company’s reactor, facility and planned operations.
Last Energy said in a May 28 press release this approval moves it closer to DOE authorization to bring nuclear fuel on site, demonstrate criticality and operate its reactor. The company said that its fuel has been manufactured. .
“Our team has advanced building construction, equipment procurement, fuel fabrication, and safety documentation in parallel, reflecting the disciplined execution this project requires,” Adam Lenarz, Last Energy vice president of development, said. “With this milestone complete, we are focused on finalizing the DSA [documented safety analysis], the final safety analysis needed to secure DOE authorization for fuel receipt, criticality, and reactor operations.”
Under the reactor pilot program, Last Energy is planning to build its PWR-5 test reactor at Texas A&M-RELLIS. The company signed a land lease with the university in October 2025 and began construction this year and procured and delivered reactor components to the site to build up its test reactor.
Texas A&M RELLIS is designed to be a research and development campus for new technology.
The PWR-5 test reactor will use the same physical reactor size as Last Energy’s PWR-20 reactor, but will have a reduced fuel enrichment scaled to five megawatts. Its PWR-20 reactor is a transportable 20-megawatt pressurized water microreactor.
While the company has not deployed a commercial reactor yet, it aims to build out this rapid on-site assembly microreactor for industrial customers, data centers and other high-energy users.
Last year, Last Energy relocated its headquarters from Washington, D.C. to Austin, Texas.