RELEASE: Valar Atomics Achieves First Criticality in DOE Pilot Program

WASHINGTON, DC - November 17, 2025 – Valar Atomics announced that its NOVA Core successfully achieved criticality at Los Alamos National Laboratory’s (LANL) National Criticality Experiments Research Center (NCERC) today at 11:45 am PT. This milestone makes Valar the first company in the U.S. to reach criticality under the U.S. Department of Energy’s Reactor Pilot Program.

“Achieving cold criticality represents a milestone for Reactor Pilot Program participants and meets the goal outlined in the recent executive order. This is one step of many toward a functional commercial product,” said Dr. Adam Stein, Director of Nuclear Energy Innovation. “The Reactor Pilot Program is well-suited to enable and accelerate this type of innovation and early testing that helps developers to validate and optimize designs.”

The DOE Pilot Program, established under Executive Order 14301, aims for at least three test reactors to reach criticality by July 4, 2026. Valar’s achievement aligns with the broader national intent of the DOE’s pilot program, which is meant to provide a vital prototyping and demonstration platform for advanced reactors. Valar’s announcement explains the significance of this milestone:

Zero-power criticality, or “cold criticality”, is the foundational milestone which precedes nuclear operation with power. It is a self-sustaining chain reaction of uranium-235 within a nuclear core, but without reaching full operating temperatures or actively removing heat with a working fluid. Zero-power criticality allows Valar to gain a greater understanding of the neutronic characteristics of the core and verify assumptions about fuel, moderators, active reactivity control, and burnable poisons.

Valar is pursuing a high-temperature gas-cooled, graphite-moderated reactor employing HALEU TRISO fuel. Valar completed a criticality test on an assembly called NOVA that models a subsection of their Ward250 core. The Ward 250 project is separate and supposed to begin power operations next year under the Pilot Program in Utah.

Valar’s successful test is an achievement for the Pilot Program itself; it is working as intended, providing a platform that enables nuclear developers to test, iterate, and innovate on their designs. Both Valar and DOE have now shown proof of concept.

Valar’s NOVA core will continue testing at NCERC over the next several weeks. LANL will conduct a variety of experiments to help improve the knowledge base and future operation of Valar’s reactor. The testing will provide data required to inform high-temperature operations in a different reactor system.

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Media Contact:

Adam Stein

Director of Nuclear Energy Innovation

adam@thebreakthrough.org