Hermes

Overview

35 MWth low-power demonstration reactor validating Kairos Power's KP-FHR design, construction methods, fuel program, and operating approach in Oak Ridge, Tennessee.

Construction permit granted in December 2023 and nuclear safety-related construction began in May 2025. In May 2026 the NRC extended the construction-completion deadline by 28 months to April 30, 2029 after first-of-a-kind site and design delays; Kairos now expects to finish building the reactor in 2028, pushing operation past the original 2027 target.

Key Specs