X-Energy, a developer of advanced nuclear reactors and fuel technology, has finalized a binding agreement with industrial materials manufacturer SGL Carbon to double SGL’s production capacity for NBG-18 medium-grain isotropic graphite. The specialized material serves as a foundational structural component for X-energy’s proprietary Xe-100 high-temperature gas-cooled reactor (HTGR).
The multi-million-dollar supply chain expansion secures critical, long-lead materials to support the execution of X-energy’s commercial pipeline, which currently exceeds 11 gigawatts (GW).
Expanding Global Manufacturing for Safety-Critical Components
Under the terms of the agreement, X-energy will invest up to $8 million in milestone-based capital contributions toward facility enhancements and equipment upgrades at SGL’s manufacturing plant in Chedde, France. The capital expansion will enable the site to produce raw graphite billets sufficient to support up to eight new Xe-100 reactor units annually.
In tandem with the European expansion, SGL has committed to expanding its domestic U.S. processing infrastructure for machining raw billets into precision graphite blocks, reinforcing supply chain continuity across transatlantic operations. Upon full completion by 2030, the joint investment will effectively double total European production capacity for NBG-18 graphite. Both companies are also evaluating supplemental regional investments to further eliminate production bottlenecks during initial billet fabrication.
Also Read: Interlune and Vermeer Expand Partnership to Build Infrastructure for a Permanent Lunar Presence
Building on a Multi-Million-Dollar Supplier Framework
This binding capacity agreement expands upon a 10-year Supplier Framework Agreement originally established in January 2026, which featured an initial three-year contract valued at over $100 million for X-energy’s inaugural commercial builds.
Initial NBG-18 graphite billets manufactured at the Chedde facility under the agreement have already been shipped to SGL’s U.S. manufacturing hubs for final precision machining. This operational milestone follows a successful prototyping campaign conducted earlier this year, which involved rigorous non-nuclear testing and structural validation at X-energy’s Technology Advancement Center (XTAC) in Frederick, Maryland.
“Commercializing new nuclear at scale rests first and foremost on our ability to significantly expand the 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.
The Operational Role of NBG-18 in Advanced Nuclear Architectures
NBG-18 is a specialized, nuclear-grade graphite designed to perform dual roles within the Xe-100 pebble-bed reactor core: functioning both as a neutron moderator and as a central structural matrix.
Originally developed during South Africa’s Pebble Bed Modular Reactor initiative and subsequently refined under the U.S. Department of Energy’s (DOE) Next Generation Nuclear Plant project—two direct technological predecessors to the Xe-100—NBG-18 possesses extensive qualification data validating its structural integrity and performance durability across decades of extreme high-temperature operation.
Initial production runs of NBG-18 will support X-energy’s debut commercial deployment: a proposed four-unit Xe-100 power facility developed in partnership with Dow under the U.S. Department of Energy’s Advanced Reactor Demonstration Program. The remaining capacity allocations ensure long-lead component readiness for subsequent commercial projects, reinforcing a global supply chain ecosystem built for fleet-scale nuclear energy deployment.