An AI data center powered by a waterless reactor is one step closer. Valar Atomics, the startup behind that plan with Nvidia, has closed a $1B Series B led by Sequoia Capital, with an extra $200M credit facility and Sequoia partner Shaun Maguire joining the board.
Valar aims to move from a single test reactor in Utah to assembly-line production of small units. It plans to make its own TRISO fuel and use helium as coolant, with fuel labs built on the same sites as the reactors, so reactor and fuel are treated as one manufacturing problem.
The company’s Ward 250 reactor reached self-sustaining criticality on June 18, a first for a company-run reactor outside a national laboratory. The core design had earlier been validated at Los Alamos National Laboratory’s criticality facility, where the NOVA core went critical at zero power in November 2025.
About a week after Ward 250 came online, Valar ran its current into an Nvidia Blackwell processor, and the two companies agreed to develop a waterless 30-megawatt AI factory together. That partnership frames the round: investors are funding power for the AI buildout, not just reactor physics.
Valar says each unit makes the next cheaper and faster, and it expects the cadence to compress until it is producing tens, then hundreds, of reactors a year.
