The U.S. Nuclear Regulatory Commission (NRC) has issued its Final Safety Evaluation Report (FSER) for Kairos Power's application to construct their Hermes molten salt test reactor at a site in Oak Ridge, Tennessee. Kairos says that it expects to receive a construction permit for the first of a kind reactor later this year.
The NRC evaluation concludes that there are no safety aspects that would preclude issuing a construction permit for the reactor. It comes after the agency’s independent Advisory Committee on Reactor Safeguards provided the results of its review. It recommended that the construction permit for the Hermes demonstration reactor be approved.
Kairo submitted its permit application in two parts. One in September of 2021 and a second in October of 2021. The company began extensive pre-application engagement with the NRC in 2018. The NRC accepted the Hermes CPA for review in November of 2021. It committed to an accelerated twenty-month review timeline, but it completed it in eighteen months. Andrea Veil is the director of the NRC's Office of Nuclear Reactor Regulation. She said that “This reflects the NRC's commitment to maintaining safety, by applying risk-informed approaches, while improving efficiency.”
Peter Hastings is the Kairos Vice President of Regulatory Affairs. He said, “We look forward to continuing our close collaboration with the staff and the Commission to support the Final Environmental Impact Statement and complete the mandatory hearing.”
Kairos is taking what they call an “rapid iterative” approach to development. The company says that this reduces risk on the path to commercialization and establishes confidence for build and construction. The company will have to submit a separate application in the future to obtain an operating license. It said that the Hermes construction permit application is laying the groundwork for this application. This will generate lessons to inform the license applications for future commercial development.
Hermes will be a thirty-five megawatt thermal non-power version of the company’s fluoride salt-cooled high temperature reactor called the KP-FHR. This reactor uses TRISO fuel pebbles with a low-pressure fluoride salt coolant. The demonstration Hermes reactor has been selected by the U.S. Department of Energy (DoE) to receive six hundred and twenty nine million dollars in cost-shared risk reduction funding over seven years under the Advanced Reactor Demonstration Program. It 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 Hermes reactor. TRISO fuel pebbles to fuel the reactor will be produced at the Los Alamos National Laboratory's Low Enriched Fuel Fabrication Facility under an agreement announced in late 2022. Kairos has also commissioned a plant to produce high-purity fluoride salt coolant known as Flibe in partnership with Materion Corporation. The Molten Salt Purification Plant, in Elmore, Ohio, has shipped its first batch of the molten salt coolant to Kairos’ testing facility in Albuquerque, New Mexico, to support Engineering Test Unit (ETU) operations, the company said in a separate announcement.