Nuclear Startups Chase the July Fourth Goal

Valar Atomics hits a vital physics milestone at Los Alamos, signaling a shift from paper theories to tangible hardware in the race for clean power

20 Nov 2025

Valar Atomics has achieved a sustained nuclear reaction at a testing facility in New Mexico, marking a significant step in the development of its small modular reactor. The company reached "zero-power criticality," a state where a nuclear chain reaction becomes self-sustaining without generating heat or electricity.

The achievement at the National Criticality Experiments Research Center follows a broader push by the US Department of Energy to accelerate advanced nuclear designs. Under the Reactor Pilot Program, federal officials aim to have several test reactors reach this stage by July 2026. This timeline reflects a shift in policy intended to shorten the period between laboratory research and industrial application.

This milestone arrives as US electricity demand projections rise for the first time in decades. Growth is driven largely by the expansion of data centers and the electrification of heavy industry. Unlike wind or solar, nuclear power provides "firm" energy that remains available regardless of weather conditions.

Institutional interest is rising alongside technical progress. Radiant Industries, a competitor in the microreactor space, recently secured more than $300m in funding. While Radiant focuses on portable units for defense and remote areas, Valar Atomics is targeting larger industrial users.

"The achievement signals measurable technical progress in a sector often defined by long development timelines," noted the Breakthrough Institute. The validation of physics models at this stage is intended to reduce risk for private investors and federal regulators.

However, the path to commercial deployment remains steep. Significant hurdles persist in the form of fuel supply chains and the high capital costs associated with first-of-a-kind builds. Valar Atomics must still navigate a multi-year licensing process and fuel qualification before any reactor can provide power to the grid.

A success of the "cold criticality" test moves the design from a theoretical model into a verified system. The coming years will determine if such technical milestones can be converted into a scalable solution for the American energy market.