Kairos submitted its permit application in two parts, in September and October 2021, but the company began extensive pre-application engagement with the NRC in 2018. The NRC accepted the Hermes construction permit application (CPA) for review in November 2021.
In June, the NRC issued a Final Safety Evaluation Report (FSER) for the application. NRC's evaluation concluded that there are no safety aspects that would preclude issuing a construction permit for the reactor.
After weighing the facility's environmental, economic, technical and other benefits against environmental and other impacts, NRC staff have now issued the FEIS, also recommending that the permit should be issued.
"This is the final document from NRC staff to support the commission hearing planned later this year and marks the formal conclusion of the environmental review for the Hermes construction permit application," Kairos noted.
The NRC staff will provide the FEIS and FSER to the commission for the mandatory hearing phase of the licensing process. Following the hearing, expected to take place later this year, the commission will vote whether to authorise the staff to issue the permit.
"We are grateful to the NRC staff for their thorough review and comprehensive engagement with us and with local stakeholders," said Kairos Site Licensing Manager Marty Bryan.
"The FEIS follows extensive engagement between Kairos Power and the NRC beginning in 2018," added Darrell Gardner, senior licensing director at Kairos. "It builds upon selecting and characterising an appropriate site for Hermes, engaging with the local community, and continuously communicating with stakeholders. We applaud the staff's steady progress toward closing out the Hermes CPA review and look forward to completing the mandatory hearing later this year."
The company will have to submit a separate application for an operating licence and obtain approval from the NRC before operating the Hermes reactor.
Hermes will be a 35 MW (thermal) non-power version of the company's fluoride salt-cooled high temperature reactor - the KP-FHR, which uses TRISO (TRI-structural ISOtropic) fuel pebbles with a low-pressure fluoride salt coolant. The demonstration reactor has been selected by the US Department of Energy to receive USD629 million in cost-shared risk reduction funding over seven years under the Advanced Reactor Demonstration Program, and is intended to provide operational data to support the development of a larger version for commercial deployment.
A site at the East Tennessee Technology Park in Oak Ridge has been selected for the demonstration reactor, and TRISO fuel pebbles will be produced at the Los Alamos National Laboratory's Low Enriched Fuel Fabrication Facility under an agreement announced in late 2022. The company has also commissioned a plant to produce high-purity fluoride salt coolant - known as Flibe - in partnership with Materion Corporation.
Last month, Kairos submitted an application to the NRC for permission to build the Hermes 2 plant next to the Hermes reactor at Oak Ridge. Comprising two 35 MW (thermal) reactors - each the same size as the original test reactor - and sharing a power generation system, the Hermes 2 plant would produce and sell electricity. The NRC is now assessing that application to determine if it is acceptable and complete enough to begin the formal technical review process.
