Overview
- The Department of Energy confirmed late on June 18 that Valar Atomics’ Ward 250 achieved a zero‑power fueled criticality test at the San Rafael Energy Lab in Emery County, Utah.
- Zero‑power fueled criticality means the reactor sustained a self‑sustaining fission chain reaction at negligible power to validate core physics without full cooling or power conversion systems operating.
- The test makes Ward 250 the second reactor to go critical under the DOE Reactor Pilot Program and the first DOE‑authorized reactor built and run outside a national laboratory.
- Valar says Ward 250 has begun non‑commercial power ascension with integrated systems in place and that the company is targeting a near‑term demonstration of producing power before July 4.
- Significant next steps remain including further integrated tests, stable TRISO/HALEU fuel supply, and NRC commercial licensing, and those factors will determine whether these Pilot Program demos translate into wider commercial deployment.