The US Department of War (DOW – formerly Department of Defense) and the Department of Energy (DOE) have partnered to support the transportation of Valar Atomics’ Ward250 reactor to the Utah San Rafael Energy Lab (USREL). The reactor was transported using C-17 Globemaster III military transport aircraft from March Air Reserve Base in California to Hill Air Force Base in Utah in a first-of-its-kind airlift of a nuclear reactor, dubbed Operation Windlord.
US Energy Secretary Chris Wright accompanied the reactor to its destination. “One of President Trump’s core missions when he assumed the presidency was to unleash American energy dominance,” Wright said during a press conference at the March Air Base. “He recognised that more energy made America stronger economically, (with) more job opportunities in our country (and) stronger militarily, better able to project power abroad.”
“This activity marks a tremendous milestone, and the meaningful logistics trials that will inform the department’s understanding of the capabilities required to harness advanced nuclear power,” said Michael Duffey, Undersecretary of War for Acquisition and Sustainment.
Valar’s head of projects, Max Ukropina noted: “Soon, the Department of War can deploy to every single war zone, humanitarian mission or remote installation, meeting mission-critical power, safeguarding troops and deterring adversaries. Moreover, these scalable units will fortify domestic bases with secure power, insulated from aging electrical.”
California-based nuclear start-up Valar Atomics was founded in 2023 and emerged from stealth in February 2025. It was one of 11 companies selected in June 2025 by DOE for its Reactor Pilot Program, which aims to achieve criticality for three reactors by 4th July 2026 in line with President Trump’s May Executive Order 14301.
Valar was also one of four companies selected by DOE in September to take part in its Fuel Line Pilot Program which leverages the DOE authorisation process to build and operate nuclear fuel production lines for research, development, and demonstration purposes and to provide a fast-tracked approach to commercial licensing. The Fuel Line Pilot Program supports the Reactor Pilot Program and establishes a domestic nuclear fuel supply chain for testing new reactors.
Ward 250 is a 100 kWt high temperature gas-cooled reactor (HTGR) design that uses TRISO fuel, helium coolant and graphite moderators. It aims to build America’s first nuclear gigasites – clusters of thousands of HTGRs designed to produce industrial power and carbon-based fuels cheaper than oil.
In September 2025 Valar began ground-breaking for the reactor at USREL, part of the Utah Office of Energy Development (OED). Since then, the site has transitioned from ground-breaking to heavy vertical construction and component delivery. Local contractors had finished moving and crushing approximately 40,000 cubic yards of material by late January 2026. Over 4,000 cubic yards of concrete have been poured for the foundations of the Ward250 reactor and the on-site fuel fabrication facility, which is being built alongside the reactor.
For shipment to USREL, the reactor was broken down into eight distinct modular units to fit the cargo dimensions of the C-17 aircraft. The reactor was transported without nuclear fuel (unfilled) to comply with safety regulations and simplify the airlift logistics. The hardware includes the reactor vessel, graphite moderators, and helium cooling systems. Digital “fly-by-wire” style control systems, similar to those validated in the Ward Zero prototype, were integrated into the modules.
A convoy of three C-17 Globemaster III aircraft was used to carry the eight modules. Upon landing at Hill Air Force Base, the modules were loaded onto a specialised truck convoy for final delivery to USREL in Emery County. Crews will now begin the complex process of joining the eight modules into a single functional unit.
The reactor will undergo non-nuclear thermal testing at USREL to ensure the helium seals and graphite moderators perform at operational temperatures. Once the on-site fuel fabrication facility is ready, planned for this spring, the TRISO fuel will be inserted to meet the 4 July criticality target.
Valar Atomics has also developed the WardZero, a non-nuclear, thermal prototype used for testing. WardZero is a 1:1 scale model designed to mimic the physical, thermal, and mechanical properties of the Ward250 reactor. It is used to test the reactor core’s structural integrity, helium leak-rate targets, and thermal performance at full operational temperatures (above 750°C). Using silicon carbide heaters instead of nuclear fuel, Valar tested the components and design philosophy that are now being implemented in the Ward250.
Additionally, Valar developed a “NOVA Core” (a subset of the Ward250 design) for cold criticality testing at Los Alamos National Laboratory (LANL) to validate the physics of the Ward250 before its full operation. In December 2025, the NOVA Core achieved zero-power criticality at LANL’s National Criticality Experiments Research Center (NCERC) at DOE’s Nevada National Security Site (NNSS).
Zero-power criticality (cold criticality) 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.
“Zero power criticality is a reactor’s first heartbeat, proof the physics holds,” said Isaiah Taylor, Founder & CEO, Valar Atomics. “I’m incredibly proud of the Valar team that took this from blueprint to splitting the atom, securing the first criticality ever achieved by a venture-backed company.” Valar raised $130m in a November 2025 funding round bringing its total fundraising to $150m. The round was backed by Anduril Industries founder Palmer Luckey and Palantir Chief Technology Officer Shyam Sankar.
