In Development
Hermes
35 MWth low-power demonstration reactor validating Kairos Power's KP-FHR design, construction methods, fuel program, and operating approach in Oak Ridge, Tennessee.
Kairos PowerHermes 2
In Development
Commercial-scale demonstration plant that extends the Hermes learning loop into electricity production for the TVA grid and Google-backed demand.
Latest update Sep 20, 2026
01
Current status
NRC construction permits were issued in November 2024 and Kairos broke ground on the plant on April 17, 2026 - the first deployment under its Google-backed fleet plan. Kairos has re-envisioned Hermes 2 as a single-reactor, up-to-50 MWe plant scheduled to begin operations around 2030. On September 4, 2026 the company completed ETU 3 Phase 1, a reduced-scale Hermes 2 reactor-cavity mockup used to test modular precast shielding and remote robotic maintenance before those methods are applied to the licensed plant. A September 10 update said ETU 2 in Albuquerque is integrating more than 30 factory-built skids and that Hermes 2 will use the same Albuquerque-to-Oak Ridge modular construction path.
02
Specifications5
03
Upcoming milestones2
Announced next steps from Kairos Power that mention Hermes 2.
Later in 2026
Complete ETU 2 integration and hot argon testing
Finish module installation and piping/electrical connections on Engineering Test Unit 2's more than 30 factory-built skids in Albuquerque, then run hot argon testing (valves, inert gas, temperatures and pressures) before heating the Flibe salt system. Kairos described ETU 2 as the world's largest planned Flibe molten-salt test once operations start later in 2026, and said the modular path will feed Hermes 2 construction.
2030
Deliver first Google-backed grid power
Advance Hermes 2 into operation as the first TVA-grid deployment under Kairos Power's Google agreement, proving the transition from demonstration to commercial power sales. Newly appointed VP of Operations and Site Delivery Mike McGuire (Aug 3, 2026) is tasked with taking the plant from construction through commissioning. ETU 3 Phase 1 (completed Sept 4, 2026) is feeding shielding and remote-maintenance lessons into the Hermes 2 cavity design, and a September 10 update said Hermes 2 will use factory-built skids fabricated in Albuquerque - the same modular path now being integrated on ETU 2.
04
In the news2
Samsung C&T backs Kairos Hermes 2 with up to $100M
Kairos Power and Samsung C&T Engineering and Construction Group signed a binding term sheet on September 21 for Samsung C&T to provide up to $100 million in a mix of direct investment and in-kind engineering services, subject to regulatory approvals, to support the Hermes 2 plant in Oak Ridge, Tennessee. Samsung C&T will join Kairos's integrated EPC team, initially on power-generation systems and balance of plant, while Kairos leads the nuclear island. The cash-versus-services split was not disclosed. Untracked Samsung C&T is the counterparty.
www.kairospower.com www.world-nuclear-news.org www.kairospower.com
Kairos Power validates first molten-salt reactor fuel code
Kairos Power completed verification and validation of KP-BISON, the first fuel performance code built for a molten-salt reactor, on July 16, 2026. The code models how TRISO fuel particles behave and hold structural integrity at the high temperatures inside Kairos's fluoride salt-cooled reactor design, and the company plans to submit the reports to the NRC as part of the licensing basis for its Hermes 2 demonstration plant.
05
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06
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