US collaboration fortifies nuclear-grade graphite supply chain

California-based Radiant is developing the 1MW Kaleidos high-temperature gas-cooled portable microreactor, which will use a graphite core and TRISO (tri-structural isotropic) fuel. It was one of three microreactor developers selected last year to receive a share of USD3.9 million US Department of Energy funding to develop and test their designs in the new Demonstration of Microreactor Experiments (DOME) test bed facility at Idaho National Laboratory. Testing is scheduled to begin in 2026, and Radiant says it is aiming for commercial production units in 2028.

However, the company says the success of the Kaleidos demonstration project and the viability of subsequent commercial projects "will depend in critical part on supply certainty and affordability of nuclear-grade, medium and fine grain graphite required for application in a nuclear environment".

Formalising its strategic relationship with Amsted Graphite Materials, which is the largest US-owned synthetic graphite producer, will secure a reliable supply of these materials, Radiant Chief Operating Officer Tori Shivanandan said: "By joining forces to secure a reliable supply of critical graphite materials, we are investing in the success of our Kaleidos Demonstration Project and laying a solid foundation for the future of clean energy in the United States."

Key objectives outlined in the memorandum of understanding (MoU) between the two companies include collaborative efforts in policy advocacy at federal, state and local levels, strategic discussions with third parties, exploration of public-private partnerships with the US government, and participation in testing and R&D programs with universities and government laboratories. The companies say the MoU "underscores the mutual commitment of Radiant and Amsted Graphite Materials to reduce reliance on foreign sources of nuclear-grade graphite, enhance US advanced manufacturing capabilities and bolster the security of US nuclear energy supply chains".

Graphite has been used in nuclear reactor cores as a moderator, slowing down the neutrons released from nuclear fission so that the nuclear chain reaction can be maintained. Most of the power reactors currently in commercial operation - with the exception of the UK's advanced gas-cooled reactor fleet and the Soviet-designed graphite moderated, water cooled RBMK - use light or heavy water as the moderator, but advanced reactor designs, including high-temperature gas-cooled reactors and molten salt reactors, use graphite moderators.

Amsted Graphite Materials signed a partnership agreement to establish an integrated domestic supply chain for nuclear-grade graphite with small modular reactor developer X-energy in 2022. X-energy’s Xe-100 high-temperature gas-cooled reactor is designed to use synthetic graphite as a moderator.