Valar Atomics achieved first criticality and completed zero-power testing at Ward 250, a Generation IV HTGR microreactor at the Utah San Rafael Energy Lab. Second advanced reactor to go critical under DOE's Reactor Pilot Program and first DOE-authorized reactor built and operated outside the national laboratory system. The HTGR microreactor, slightly larger than a minivan, is designed to generate up to 5 MWe. Non-commercial power ascension has begun. The reactor was built in approximately 9 months from an empty site and is the second of multiple advanced reactors anticipated to achieve criticality under the July 4, 2026 deadline set by President Trump's May 2025 executive order.