Valar Atomics achieves first criticality test in collaboration with Los Alamos National Laboratory
Nov 18, 2025
Key Points
- Valar Atomics achieved first criticality of its Nova Core reactor at Los Alamos National Laboratory, clearing a key gating milestone toward commercializing small modular reactors.
- Valar contributed the reactor core and TRISO fuel while Los Alamos supplied the critical assembly facility and oversight, prompting debate over whether the startup is doing engineering execution or relying on government infrastructure.
- Founder Isaiah Taylor frames Valar's mission as engineering-driven deployment, not scientific discovery, betting that manufacturing capability and regulatory clarity can revive nuclear as a dormant industrial sector.
Summary
Valar Atomics achieved first criticality of its Nova Core reactor in collaboration with Los Alamos National Laboratory. The reactor went critical at 11:45 a.m., according to founder Isaiah Taylor.
Valar provided the reactor core, TRISO fuel, and system configuration. Los Alamos supplied the critical assembly facility, safety envelope, and experimentalist oversight. Some observers questioned whether Valar had contributed novel science or primarily relied on Los Alamos infrastructure.
Valar's mission is engineering execution at scale, not breakthrough physics. Fission was discovered 80 years ago and worked. The U.S. stopped building reactors and let the technology become unprofitable and regulatory-constrained while China copied the approach and moved forward. American reindustrialization in nuclear requires generating as much energy as possible for as little money as possible. That requires deployment, not discovery.
Valar's approach mirrors Elon Musk's framing for xAI. The company employs engineers, not scientists. The mission is to build a small modular reactor and bring it online—incremental progress toward a concrete commercial goal, not foundational research. Taylor has framed his ambition as wanting to be "the Elon of nuclear," not the Oppenheimer of nuclear. The U.S. remains capable of manufacturing bus-sized objects efficiently. Valar's wager is that this engineering capability, combined with regulatory clarity and capital, can revive a dormant industry.
The test clears a gating milestone by demonstrating that a startup-designed reactor core can achieve criticality under professional oversight. It moves Valar closer to its actual deliverable: a functioning small modular reactor.