Netherlands research institute NRG PALLAS has signed a contract with US-based Kairos Power to assess materials and fuels that will be used in the small modular reactors (SMRs) Kairos is developing to power Google data centres.

In 2023, the US Nuclear Regulatory Commission (NRC) issued a construction permit for Kairos Power’s Hermes demonstration reactor – the first non-water-cooled reactor to be approved for construction in the US in more than 50 years. The Hermes design is for a 35 MWt non-power version of the company’s fluoride salt-cooled high temperature reactor, the KP-HFR.

Kairos has also submitted a construction permit application for Hermes 2, a proposed two-unit demonstration plant that would build on the experience of Hermes and would produce electricity and demonstrate the complete architecture of future commercial plants. Kairos is targeting commercial deployments in the early 2030s. Hermes is to be built at Oak Ridge.

NRG PALLAS has more than 50 years of experience in nuclear fuel research. Using the High Flux Reactor (HFR) in Petten, NRG PALLAS simulates ageing processes in an accelerated manner, measuring the irradiation of materials and fuels to assess their safe use in nuclear reactors. The newly built PALLAS-reactor, which will replace HFR, will continue this work, ensuring long-term continuity.

Kairos has signed several agreements with NRG PALLAS to perform irradiation demonstration and qualification of fuels and materials to support the KP-FHR commercial programme. The fuel irradiation programme at HFR will demonstrate the performance envelope needed for successful KP-FHR commercial operations. This will enable Kairo to demonstrate to NRC how the fuel satisfies safety and performance requirements.

Kairos is also collaborating with NRG PALLAS on graphite irradiation testing as a demonstration of the graphite reflector structure used in the KP-FHR reactor core. NRG PALLAS has been carrying out research for Kairos on the use of graphite for many years. The new contracts mark an important continuation of this long-term relationship.

NRG PALLAS will perform irradiation services that characterise the graphite’s response to high levels of neutron exposure and demonstrate the safety limits for the graphite structures. The post-irradiation properties of graphite are an important metric in NRC licensing and inform the safety of the reactor technology.

In addition, NRG PALLAS is supporting Kairos with irradiation testing of the stainless-steel material used for the reactor vessel and structural components to demonstrate safety and design limits for important licensing activities with NRC.

“With the current digitalisation, the demand for electricity is increasing,” said Arjan Vreeling, Manager R&D Nuclear Fuels & Materials at NRG PALLAS. “We are proud that Kairos Power, a major player in the field of advanced reactors, has commissioned this innovative research from us.”

Micah Hackett, Kairos Vice President, Fuels & Materials said: “Kairos Power depends on precise and reliable irradiation performance data to advance our reactor technology, supporting both design and licensing efforts. With decades of expertise in generating superior irradiation data, NRG PALLAS is a trusted partner, helping Kairos Power meet cost and schedule commitments for Google and our future customers.”