The US Nuclear Regulatory Commission (NRC) has published its final environmental assessment and finding of no significant impact for Kairos Power’s application for construction permits to build the dual unit Hermes 2 test reactor project in Oak Ridge, Tennessee.

Concurrently, the agency issued exemptions for Hermes 2 from NRC regulations that require an environmental impact statement to support construction permits for test facilities. The site was previously evaluated with an environmental impact statement for the Hermes 1 test reactor, which the staff believed was sufficient to support the exemption. The environmental assessment considered potential impacts of aspects unique to the Hermes 2 project.

NRC staff will provide the Hermes 2 environmental assessment and its safety evaluation of the project to the Commission for the final phase of the licensing process. The Commission will determine if the staff’s review supports the findings necessary to issue the permits and vote on whether to authorise them.

The proposed Hermes 2 project comprises two fluoride salt-cooled, high-temperature reactors. Kairos Power submitted its application for construction permits in July 2023. The company will need to submit a separate application for Hermes 2 operating licences in the future.

In August, Kairos contracted Barnard Construction Company to perform site work and excavation at the Hermes site in Oak Ridge. Barnard and Kairos Power have also started collaborating on construction of the third Engineering Test Unit (ETU 3.0) – a non-nuclear demonstration co-located in Oak Ridge that will generate supply chain, construction, and operational experience to inform the Hermes project.

Hermes is a fluoride salt-cooled high-temperature reactor targeted for operation in 2027, Hermes will leverage proven technologies that originated in Oak Ridge – a combination of TRISO coated particle fuel and high-purity fluoride salt coolant – known as FLiBe – a eutectic mixture of lithium fluoride and beryllium fluoride.