The DOME (Demonstration of Microreactor Experiments) facility is a purpose-built test environment at Idaho National Laboratory's Contained Test Facility, designed to host prototype microreactor demonstrations in a setting with pre-established safety analyses, environmental approvals, and operational infrastructure. DOME provides reactor developers with a controlled environment for first criticality testing, thermal performance validation, and operational demonstration without the multi-year burden of independently developing a test site, obtaining environmental permits, and establishing emergency planning infrastructure. The facility was developed by the National Reactor Innovation Center (NRIC) specifically to accelerate the microreactor deployment timeline by removing infrastructure barriers.
Radiant Industries is the highest-profile DOME user, targeting first criticality of its Kaleidos portable microreactor at the facility on July 4, 2026. Kaleidos is a 1 MWe helium-cooled, graphite-moderated microreactor using HALEU TRISO fuel, designed for rapid deployment and transportability by truck. The DOE approved Radiant's DARK safety documentation in February 2026, clearing a key regulatory prerequisite for the DOME test. If successful, this would represent one of the first advanced reactor criticality achievements in the United States and provide invaluable data for Radiant's NRC licensing pathway toward commercial production at its R-50 facility in Oak Ridge, Tennessee, with a planned capacity of 50 units per year. Radiant's customers include Equinix (20 reactors for digital infrastructure) and the U.S. Air Force/Defense Innovation Unit (FOAK delivery 2028).
Westinghouse's eVinci heat pipe microreactor is also slated for DOME testing, with a 1/5-scale prototype planned for evaluation as early as 2026. The eVinci is a 5 MWe solid-core heat pipe reactor designed for remote and defense applications, with Penn State University partnered for prototyping and educational deployment since March 2025. The DOME facility's ability to accommodate multiple reactor technologies, from Radiant's gas-cooled design to Westinghouse's heat pipe concept, demonstrates its value as shared national infrastructure. By hosting successive demonstrations from different developers, DOME builds an expanding body of operational data and regulatory experience that benefits the entire microreactor sector, while the concentrated expertise at INL provides efficient oversight and support capabilities that would be impossible to replicate at dispersed commercial sites.