Westinghouse Electric CompanyIn Development
Transportable 5 MWe heat-pipe-cooled microreactor with TRISO fuel and no water cooling, designed to run for eight-plus years without refueling - targeting remote communities, mining, industry, data centers, and military installations.
Latest update Sep 19, 2026
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First microreactor developer to complete front-end engineering (FEEED) and win DOE approval of its Preliminary Safety Design Report for the DOME test bed at Idaho National Laboratory. Nuclear Engineering International reported on August 27, 2026 that Radiant Kaleidos is scheduled to occupy DOME first from mid-to-late 2026, with Westinghouse's scaled prototype to follow in 2027-2028. On September 3, 2026 eVinci reached zero-power high-temperature criticality at 663 C at NCERC, with a subcritical reactivity measurement at 1,011 C (announced September 15). Selected by the US Air Force and Defense Innovation Unit in April 2026 for deployment at Malmstrom Air Force Base, and on August 26, 2026 selected by the US Army for the next phase of its Janus Program at Fort Drum, New York, under a program-level goal of at least one Army-regulated reactor producing electricity by September 30, 2028. The previously targeted 2029 commercial deployment with the Saskatchewan Research Council was cancelled in fall 2025; SRC confirmed that cancellation to POWER on August 26, 2026 as Westinghouse shifted eVinci toward defense, space, and government uses.
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Announced next steps from Westinghouse Electric Company that mention eVinci microreactor.
Sep 30, 2028
On August 26, 2026, Westinghouse Government Services was selected for the next phase of the US Army's Janus Program, a $2.2B, five-year initiative backed by the Department of War's Defense Innovation Unit to build and operate more than 20 commercial nuclear microreactors across military installations. Westinghouse's eVinci microreactor was matched to Fort Drum, New York as one of five initial sites awarded to five reactor developers. The Janus Program aims to have at least one Army-regulated nuclear reactor producing usable electricity at a domestic installation by September 30, 2028, the date set by Executive Order 14299. The selection follows eVinci's August 24, 2026 zero-power criticality milestone at the Nevada National Security Site.
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Westinghouse said on September 15 that the eVinci microreactor completed zero-power high-temperature criticality testing at the National Criticality Experiments Research Center in Nevada with Los Alamos and the Nevada National Security Site. On September 3 the test reached criticality at 663 C, and researchers made a subcritical reactivity measurement at a peak core temperature of 1,011 C, a record for a reactivity measurement at NCERC. The work continues August's zero-power tests and feeds temperature-dependent data into prototype design ahead of a still-pending fueled DOME run at Idaho National Laboratory.
Westinghouse completed zero-power criticality testing for its eVinci microreactor on August 24, working with Los Alamos and Idaho National Laboratories at the National Criticality Experiments Research Center on the Nevada National Security Site. The test validated the reactor's physics models and core design assumptions rather than generating heat or power, marking a design-basis milestone for the heat-pipe-cooled microreactor as Westinghouse targets US commercial deployment by 2027 and a first unit for Saskatchewan Research Council by 2029.
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Generation III+ pressurized water reactor with fully passive safety systems and modular construction - the only fully designed and licensed advanced large reactor operating in the United States, and the reference design for the US nuclear buildout and for new plants in Poland, Bulgaria, and Ukraine.
330 MWe (990 MWt) single-loop small modular reactor derived directly from the licensed AP1000, reusing its passive safety architecture and supply chain to shorten the path through licensing and construction.
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Full-scale SMR power plant with 12 modules generating up to 924 MWe of carbon-free electricity.
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Mid-size SMR plant configuration with 6 modules producing up to 462 MWe.
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