In Development
Hermes 2
Commercial-scale demonstration plant that extends the Hermes learning loop into electricity production for the TVA grid and Google-backed demand.
Kairos PowerHermes
In Development
35 MWth low-power demonstration reactor validating Kairos Power's KP-FHR design, construction methods, fuel program, and operating approach in Oak Ridge, Tennessee.
Latest update Aug 31, 2026
01
Current status
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. As of late August 2026 no further NRC schedule action has been taken and no operating license application has yet been filed for Hermes 1.
02
Specifications6
03
Upcoming milestones5
Announced next steps from Kairos Power that mention Hermes.
2026-2027
Produce HALEU TRISO fuel for Hermes 1
Using DOE-allocated HALEU and Los Alamos National Laboratory's LEFFF capability to manufacture the first fuel pebbles needed for Hermes 1 startup and operation. As of late August 2026 Kairos has finished installing process equipment at LEFFF and is commissioning the pilot line with depleted uranium before introducing HALEU; no fuel pebbles for Hermes 1 have been reported produced yet. Company updates through September 10, 2026 (ETU 2 modular integration) did not announce a first HALEU pebble; the June 24 pebble campaign was surrogate (non-nuclear) fuel for ETU 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.
2026
Produce first HALEU TRISO pebble for Hermes 1 and file an operating-license application
TargetNeither reported as of Sep 29, 2026
2028-2029
Bring Hermes 1 online
Completing construction, fuel loading, and startup of the Hermes 1 low-power demonstration reactor in Oak Ridge to validate Kairos Power's reactor, fuel, and operating model. After a May 2026 permit amendment, Kairos expects to finish building Hermes 1 in 2028, with the NRC construction-completion deadline now set at April 30, 2029. ENR reported in late August 2026 that Barnard is installing 51 safety-related drilled piers for the Hermes 1 foundation after rehearsing the process on ETU 3.
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 news3
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 names Ignacio Redondo as first CFO
Kairos Power appointed Ignacio Redondo as its first Chief Financial Officer, the advanced nuclear reactor developer announced September 2, 2026. Redondo, most recently senior vice president of finance at solar-tracker maker Nextracker, will lead corporate fundraising, investor relations, financial reporting and compliance as Kairos scales toward serial production of its salt-cooled Hermes reactors in Oak Ridge, Tennessee.
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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