TheTechno Optimist.

Ward 250 (HTGR Demonstration Reactor)Valar Atomics—US military airlifts Valar Atomics Ward 250 reactor to Utah in historic first nuclear transportWard 250 (HTGR Demonstration Reactor)Valar Atomics—Valar Atomics Ward 250 achieves zero-power criticality, becoming second DOE reactor pilot to reach the milestone

Valar Atomics

High-temperature gas reactor, industrial heat, HTGR, TRISO fuel

USprivatevalaratomics.com (opens valaratomics.com)Checked 10 Oct

The brief

Analyst view
  • Valar Atomics reached zero-power criticality with Ward 250 in June 2026, one of four companies in the DOE pilot program.
  • The HTGR design uses TRISO fuel (tristructural isotropic) and helium cooling, enabling higher temperatures and industrial heat applications.
  • Ward 250 is located in Utah and is part of a national initiative to demonstrate next-generation nuclear technology.

Technical approach

As reported
Fuel

TRISO fuel particles

TRISO (tristructural isotropic) fuel consists of uranium kernels coated with carbon and ceramic. Each sphere survives extreme temperatures.

Cooling

Helium gas cooling

Helium gas circulates through the core and transfers heat to industrial processes. Gas cooling allows higher temperatures than water.

Design

Modular high-temperature reactor

Ward 250 is a demonstration reactor designed to prove the HTGR concept at an engineering scale, intended to be a prototype for larger commercial units.

Primer