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.