Nuclear microreactors: Companies, Startups & Research

NANO Nuclear Energy Inc., Westinghouse, Terra Innovatum and Ultra Safe Nuclear Corporation are among the companies working on nuclear microreactors. NANO Nuclear is developing the KRONOS MMR, while Westinghouse’s eVinci design uses heat-pipe cooling. Terra Innovatum is developing the SOLO micro-modular reactor and has arranged manufacturing and supply-chain partnerships.

Idaho National Laboratory, University of Illinois at Urbana - Champaign and Oak Ridge National Laboratory are prominent research organizations in the available facts. Idaho National Laboratory supports advanced reactor development, while Oak Ridge studies fuel cycles and mobile heat-pipe reactor constraints. Argonne National Laboratory is also working on high-fidelity multiphysics modeling methods for heat-pipe microreactors.

The recorded grant total is $2,215,561 across 2 grants since 2020. This figure covers grants in the available facts and is not a measure of all investment in the sector. The separate funding-round entries do not establish reactor-specific funding, so they should not be used as a reliable estimate of commercial microreactor financing.

Westinghouse Electric Corporation and Royce Rolls are the leading named patent holders, with 2 patents each in the available facts. Other listed holders include Westinghouse Electrical Sweden AB, NuScale, Valerio, Triad National Security LLC and Airbus-SAS. The named holders span reactor developers, industrial companies and research organizations.

The available facts record 11 patents in the 24-month window, but do not indicate rising patent activity. Publications reached 236 in the last year, with growth of 9.3%, while patent activity growth is reported as -42.9%. The contrast suggests that recent technical attention is more visible in research publications than in new patent filings.

Nuclear microreactors are progressing from design and analysis toward testing and licensing, but the field has not reached broad commercial deployment. Antares reported initial criticality for a TRISO-fueled design in June 2026, and the U.S. Nuclear Regulatory Commission accepted NANO Nuclear’s KRONOS MMR construction-permit application for review in May 2026. These are distinct milestones, not evidence of routine operation.

The main approaches listed are heat-pipe cooled, gas cooled, liquid-metal cooled, molten-salt and water cooled. They differ in coolant, heat-transfer mechanism, operating conditions and engineering demands. Heat pipes offer passive heat transport; gas and liquid-metal systems support different temperature and power-cycle choices; molten-salt concepts raise chemistry and materials questions; and water systems draw on familiar reactor practice.

The United States leads the available document counts with 2,865, followed by the United Kingdom with 777 and China with 576. Canada, France and Germany also feature in the country data. These figures indicate where activity is documented; they do not establish a direct comparison of deployment, operating reactors or national market share.

The listed applications are data centers and campuses, remote communities and mining, industrial energy, defense installations and space power. Data centers and campuses have 490 associated documents, while remote communities and mining have 284. These use cases call for different combinations of reliable power, transportability, site security, licensing and integration with existing energy systems.