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Valar Atomics Ward 250 achieves zero-power criticality, becoming second DOE reactor pilot to reach the milestone
Valar AtomicsWard 250 (HTGR Demonstration Reactor)
Ward 250 reached zero-power fueled criticality at Utah San Rafael Energy Lab on June 18, 2026, nine months after groundbreaking. Four companies achieved the milestone under Trump's Executive Order 14301 deadline: Antares Nuclear, Valar Atomics, Deployable Energy, and Aalo Atomics. Ward 250 is the first DOE-authorized advanced reactor built and operated outside a national laboratory.