SGL Carbon & X-energy: Capacity expansion for Nuclear-Grade Graphite
SGL Carbon and X-energy announced a binding agreement to double SGL’s production capacity for medium-grain isotropic graphite (“NBG-18”), a specialized material central to X-energy’s Xe-100 high-temperature gas-cooled reactor. X-energy and SGL Carbon’s agreement would expand the supply chain for a critical long-lead material, supporting execution of X-energy’s commercial pipeline.
Under the agreement, X-energy will invest up to $8 million in milestone-based payments to support new facilities and equipment upgrades at SGL’s site in Chedde, France, enabling the facility to produce graphite billets for up to eight new Xe-100 reactors per year. SGL Carbon has concurrently agreed to expand U.S. capacity for machining of billets into graphite blocks, helping to ensure greater supply chain continuity for a safety-critical material. Full execution would double European manufacturing capacity for NBG-18 by 2030, with additional capacity investments under consideration across multiple regions to further debottleneck initial billet production.
The expansion builds on a 10-year Supplier Framework Agreement established in January 2026, which included an initial three-year award valued at over $100 million for X-energy’s first commercial projects. The first NBG-18 graphite blocks produced under this award at SGL’s site in Chedde have since been shipped to SGL sites in the United States, for machining into components. This follows a successful prototyping campaign which began earlier this year, consisting of non-nuclear testing and validation at X-energy’s Technology and Advancement Center in Frederick, Maryland (USA) in advance of final production.
“Commercializing new nuclear at scale rests first and foremost on our ability to significantly expand the new nuclear supply chain, a challenge that extends beyond any one company, supplier, or nation,” said J. Clay Sell, CEO of X-energy. “We look forward to driving this work forward with SGL, and to engaging with potential partners who share our bold vision for a robust, resilient, U.S. and allied nuclear supply chain.”
“By jointly expanding our production capacity for nuclear-grade graphite, we are reinforcing the importance of our partnership and ensuring reliable supply to X-energy. For SGL Carbon, this agreement is a strategically important step that strengthens our position in the highly specialized growth market for nuclear-grade graphite, underscores the importance of our graphite expertise for safety-critical applications, and opens up attractive opportunities for further growth,” said Andreas Klein, CEO of SGL Carbon.
NBG-18 is a nuclear-grade graphite central to the Xe-100 design, functioning as a neutron moderator, and a structural component of the pebble-bed core. The material was first developed for South Africa's Pebble Bed Modular Reactor program, and later the U.S. Department of Energy's (“DOE”) Next Generation Nuclear Plant project, two direct predecessors to X-energy’s Xe-100. Through these, X-energy’s and SGL Carbon’s own initiatives, NBG-18 has undergone extensive qualification work for commercial nuclear operation, gathering operational data that helps to validate the material’s performance over decades of high-temperature operation.
Initial NBG-18 production is intended to support X-energy’s first commercial deployment of the Xe-100 reactor, a proposed four-unit plant in partnership with Dow Chemical Company under the Advanced Reactor Demonstration Program of the United States Department of Energy (DOE), with additional capacity secured for follow-on projects to support manufacturing readiness for safety-critical, long-lead materials. SGL Carbon’s and X-energy’s partnership is part of a growing, diversified portfolio of experienced suppliers supporting Xe-100 deployment, as well as the continued development of a global industrial supply chain.
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