Last Energy Receives DOE Approval of Pilot Reactor Documented Safety Analysis

Final Safety Analysis Approval Clears Path to DOE Readiness Review and Startup Authorization

AUSTIN, Texas--(BUSINESS WIRE)--Last Energy, an advanced nuclear technology company, announced today that the U.S. Department of Energy (DOE) has approved the company's Documented Safety Analysis (DSA) for its pilot reactor at Texas A&M–RELLIS.

The DSA is the final and most comprehensive safety analysis in the DOE authorization process. It documents in detail how Last Energy’s reactor and facility will be operated safely, building on the company's Preliminary Documented Safety Analysis (PDSA), which DOE approved in May 2026. With DSA approval complete, Last Energy moves into DOE's readiness review, the final step before DOE can issue startup authorization for criticality and reactor operations.

Last Energy's pilot reactor uses the same full-scale reactor core as its commercial reactor design. By demonstrating a full-scale core at RELLIS, Last Energy can validate commercial-ready performance and advance into power generation.

The project also uses low-enriched uranium (LEU) fuel, demonstrating a pathway to fleet-scale deployment built around an established commercial supply chain for off-the-shelf fuel.

In August 2025, Last Energy was selected to participate in DOE's Reactor Pilot Program, created under President Trump's Executive Order 14301, “Reforming Nuclear Reactor Testing at the Department of Energy.” The program is designed to accelerate reactor demonstration by authorizing test reactors through DOE's process.

Last Energy's project at RELLIS is a direct bridge to Last Energy's commercial PWR-20 deployment model. The PWR-20 is a 20 MWe micro modular nuclear plant designed for factory fabrication, standard road transport, rapid on-site assembly, and 24/7 baseload power delivery to industrial customers, data centers, and other high-energy users.

NOTES TO EDITORS

About Last Energy:

• Last Energy is a pioneering U.S. technology company focused on the fleet-scale deployment and operation of next-generation nuclear assets. With one of the industry's largest commercial microreactor pipelines, the company aims to locate its proprietary 20 MWe microreactor in strategic clusters near AI data centers and industrial facilities.
• Last Energy's commercial product, the PWR-20, is a 20 MWe micro modular nuclear plant designed for factory fabrication, standard road transport, rapid on-site assembly, and 24/7 baseload power delivery.
• Last Energy intentionally uses proven pressurized water reactor technology, standard low-enriched uranium fuel, and existing supply chains to reduce technical risk and accelerate project delivery.
• Last Energy's core innovation is its integrated reactor containment: a 1,000-ton, hermetically sealed steel structure designed for factory fabrication and no-access operation. By integrating all primary systems into a single hermetic containment, the reactor is engineered for high-throughput manufacturability and repeatable deployment.
• With a growing pipeline of microreactor projects across the U.S., UK, and Europe, Last Energy is building a repeatable model for deploying nuclear power where high-energy customers need it.