NRG-Pallas to test fuel and materials for Kairos SMR

Friday, 21 March 2025

Under the contract, NRG-Pallas will conduct fuel irradiation tests in the High Flux Reactor (HFR) to demonstrate the performance level required. Based on this, Kairos Power will be able to demonstrate to the US Nuclear Regulatory Commission (NRC) how the fuel meets the safety and performance requirements.

In addition, NRG-Pallas will perform irradiation tests that characterise the response of graphite to high levels of neutron exposure and demonstrate the safety limits of the graphite structures. The post-irradiation properties of the graphite are an important benchmark for NRC licensing and provide information on the safety of the reactor technology.

Irradiation tests will also be performed on the stainless-steel material used for the reactor vessel and structural components. The purpose of this testing is to demonstrate compliance with the safety and design requirements for licensing activities of the NRC.

NRG-Pallas said it has been conducting research into the use of graphite for Kairos Power for several years. "The new contracts are an important continuation of the long-term relationship with this innovative developer of advanced reactors," it said.

Kairos Power has adopted a rapid iterative development approach and vertical integration strategy to bring its Fluoride Salt-Cooled High-Temperature Reactor (KP-FHR) technology to market. Site work and excavation for a low-power demonstration reactor version, Hermes, began at Oak Ridge, Tennessee, last year after the NRC issued a construction permit in 2023, targeted to be operational by 2027. The NRC has also completed the final environmental assessment for the construction of the next iteration - the two-unit power-producing Hermes 2 plant - which is also planned to be built at Oak Ridge.

The KP-FHR will use fully ceramic TRISO (tri-structural isotropic) pebble-type fuel. The Hermes and Hermes 2 demonstration plants will feature units with a thermal capacity of 35 MW each. The two 35 MWt units at Hermes 2 are intended to power a common turbine generator set to produce about 20 MW electric (MWe).

Kairos envisages its commercial KP-FHR offering as dual unit plants, with two 75 MWe units for a total of 150 MWe of power output.

A deal signed in October last year by Kairos and Google will support the first commercial deployment of Kairos Power's reactor by 2030, with multiple reactors supplying clean electricity to Google data centres through power purchase agreements.

"With the current digitalisation, the demand for electricity is increasing," said Arjan Vreeling, Manager R&D Nuclear Fuels and Materials at NRG-Pallas. "Companies like Google are looking ahead and are meeting their own future energy needs with SMRs. We are proud that Kairos Power, a leading company in the field of advanced reactors, has assigned this innovative research to us."

Micah Hackett, Vice President, Fuels and Materials at Kairos Power, added: "Kairos Power depends on accurate and reliable irradiation data to advance its reactor technology and support both design and permitting processes. With decades of expertise in generating high-quality irradiation data, NRG-Pallas is a trusted partner to help Kairos Power meet its cost and schedule obligations as it builds reactors for Google."