The US Department of Energy (DOE) has selected Oklo, Terrestrial Energy, TRISO-X, and Valar Atomics for a new pilot programme to build advanced nuclear fuel lines. It will support DOE’s Reactor Pilot Program that aims to have at least three reactors achieve criticality by 4 July 2026.

“Restoring a secure domestic fuel supply will ensure that advanced reactors can move quickly from design to deployment and into operation,” said Deputy Secretary of Energy James P Danly. “The ability to produce these fuels is essential to ensuring American leadership in nuclear energy and to meeting the nation’s growing demand for reliable power.”

This is the second round of conditional selections under DOE’s Fuel Line Pilot Program. DOE previously selected Standard Nuclear to build and operate TRISO (TRi-structural ISOtropic) fuel fabrication facilities. These four projects will leverage the Department’s authorisation process to ensure a robust supply of fuel is available for research, development, and demonstration purposes, including the 11 reactors initially selected to participate in the Reactor Pilot Program:

  • Oklo (Santa Clara, California) is to build and operate three fuel fabrication facilities to support their Aurora and Pluto reactors, and possibly other fast reactors. The Aurora powerhouse design is for is a sodium-cooled fast reactor that uses metal fuel and builds on the design and operating heritage of the Experimental Breeder Reactor II (EBR-II), which ran in Idaho from 1964 to 1994.
  • Terrestrial Energy (Charlotte, North Carolina) is to develop the Terrestrial Energy Fuel Line Assembly to demonstrate a fuel salt fabrication process in a phased approach. Terrestrial is developing an Integral Molten Salt Reactor (IMSR).
  • TRISO-X (Oak Ridge, Tennessee) is to build and operate an additional fuel fabrication laboratory facility to enable pilot-scale integration, training, and system validation to support its TX-1 commercial TRISO fuel fabrication facility.
  • Valar Atomics (Hawthorne, California) is to support TRISO fuel fabrication for the Ward250 reactor deployment and potentially other high-temperature gas reactors (HTGRs). The Ward 250 design is a HTGR design that uses TRISO fuel, helium coolant and graphite moderators.

Oklo, Terrestrial Energy, and Valar Atomics were initially selected for DOE’s Reactor Pilot Program. Today’s fuel line selections aims to expand access to the advanced fuel required to test their designs and accelerate the transition from demonstration to deployment.

Each company will be responsible for all costs associated with the construction, operation, and decommissioning of their fuel fabrication facilities, and must manage the sourcing of nuclear material feedstock. Companies may apply to receive high-assay low-enriched uranium (HALEU) through DOE’s HALEU Availability Program. DOE says development of these pilot projects could drive private sector investment and create a fast-track approach to commercial licensing.

Both pilot programmes advance President Trump’s Executive Orders intended to reform nuclear reactor testing and expand US nuclear capacity for national security as part of a nuclear renaissance. The Fuel Line Pilot Program supports the Reactor Pilot Program and establishes a domestic nuclear fuel supply chain for testing new reactors. The programme leverages the DOE authorisation process to build and operate nuclear fuel production lines to serve for research, development, and demonstration purposes and to provide a fast-tracked approach to commercial licensing.

In June, DOE established a pilot programme for reactor construction and operation on sites located outside of the national laboratories in accordance with Executive Order 14301 to reform and streamline national laboratory processes for reactor testing at the Department. However, the US currently lacks sufficient domestic nuclear fuel resource capacity for this programme and DOE is relying on the same authority to develop or build fuel production lines to increase production capacity under Executive Order 14299, which seeks to deploy advanced nuclear reactor technologies for national security.  

Terrestrial Energy said its selection for the Fuel Line Pilot Program “represents a significant validation of Terrestrial Energy’s comprehensive Western supply chain strategy and marks another critical milestone in the company’s accelerated Integral Molten Salt Reactor (IMSR) commercialization pathway”.

It “directly complements the company’s recent selection for DOE’s Advanced Reactor Pilot Program announced in August 2025, creating a comprehensive framework that spans both reactor development and fuel supply chain capabilities. Together, these selections position Terrestrial Energy’s IMSR technology at the forefront of America’s nuclear renaissance while validating the company’s integrated approach to commercialisation.”

Oklo co-founder & CEO Jacob DeWitte said: “Through the Fuel Line Projects and Reactor Pilot Programs, DOE is laying the groundwork for the next wave of nuclear development and deployment, and Oklo is proud to contribute by building the advanced fuel infrastructure needed to deploy our powerhouses and strengthen US energy security.”