The U.S. Department of Energy‘s (DOE) Oak Ridge National Laboratory (ORNL) claimed the 2026 SME Aubin Additive Manufacturing Case Study Award at the SME AM Awards and TCT Awards Gala, held April 14 in Boston. The honor spotlights standout real-world deployments of 3D printing, and ORNL’s entry, focused on nuclear construction, impressed judges for its technical depth, cross-sector collaboration, and broader implications for US energy infrastructure.
The project seeks to address a persistent challenge: nuclear plant construction is notoriously slow and expensive. Concrete structures alone, including radiation shielding, can represent as much as 60 percent of a project’s schedule risk. Small modular reactors (SMRs) are increasingly central to the country’s energy strategy, yet delays in building them undermine their promise.
“Construction has been a major bottleneck for advanced reactors,” said Ahmed Hassen, group leader for composites innovation and the ORNL project lead. “We showed that digital manufacturing can cut weeks off the schedule while meeting strict nuclear standards.”
Printing Molds That Shape the Future of Nuclear
ORNL’s Manufacturing Demonstration Facility, alongside the University of Maine, Kairos Power, and other U.S. partners, applied large-format additive manufacturing (LFAM) to produce composite molds for casting the concrete elements of Kairos Power’s modular reactor shielding system. Because the Kairos reactor operates at low pressure, its concrete structures don’t require pressure-rated containment, which opened the door for this novel forming approach.
The molds were used to cast bio-shield strongback columns, roughly 8 by 8 by 20 feet, and shielding wall panels stretching up to 27 feet, some with complex interlocking joints that reduced or eliminated the need for grout. Engineers developed the molds using digital models, printed them in sections, then machined and sealed them to tolerances as tight as one-sixteenth of an inch. The forms also held up under wet concrete poured at heights of up to 12 feet.
Where traditional steel molds require six to eight weeks to fabricate and are difficult to modify, the ORNL team designed, printed, and delivered reusable composite molds in roughly two weeks. The molds were lighter than steel, easier for field crews to handle, and completed four full casting cycles for the columns and three for the wall panels, with no measurable quality loss.
From Demonstration to Deployment
The molds were validated through full-scale tests as part of Kairos Power’s reactor demonstration program, and the results are already attracting commercial interest. ORNL is now in discussions with a major U.S. precast manufacturer about scaling the methodology broadly. If adopted at scale, LFAM tooling could meaningfully compress construction timelines and reduce costs, bringing advanced reactors online sooner.
“This project shows that additive manufacturing is not just for prototypes,” Hassen said. “It can be a reliable, repeatable system for building safety-critical nuclear infrastructure to strengthen the country’s energy security.”
The project was funded by DOE’s Advanced Materials and Manufacturing Technologies Office (AMMTO) under the SM2ART Program.
A Broader Push to Rebuild Nuclear With Additive Manufacturing
The Kairos Power collaboration is part of a broader, years-long effort to modernize the U.S. nuclear industry. Most domestic nuclear power today comes from reactors built between 1967 and 1990. Decommissioning is now outpacing new construction, and the number of operational reactors has declined from a peak of 112 in 1990 to 92 in 2022, with only three large reactors coming online in the past 28 years. In response, the DOE is targeting three new test reactors by the end of 2026 and its first operational microreactor in 2028, timelines that conventional construction methods have historically struggled to meet. Additive manufacturing is emerging as a critical enabler of this accelerated schedule.
ORNL has been laying the groundwork for this transformation. In 2021, four 3D printed fuel assembly brackets, developed in partnership with the Tennessee Valley Authority (TVA) and Framatome, were installed at TVA’s Browns Ferry Nuclear Plant in Alabama, reportedly marking the first 3D printed safety-related components ever placed in an operational reactor.
More recently, ORNL pushed that boundary further by testing 3D printed rabbit capsules inside a nuclear reactor for the first time. These small stainless steel components, printed using laser powder bed fusion, house experimental materials during irradiation and must contain fission gases produced during nuclear reactions.
The convergence of AM and nuclear construction marks a turning point for an industry long constrained by legacy methods. As federal timelines accelerate and the pressure to deliver new capacity intensifies, ORNL’s work demonstrates that additive manufacturing is no longer peripheral to the solution, it is foundational to it.
3D Printing Industry is inviting speakers for its 2026 Additive Manufacturing Applications (AMA) series, covering Energy, Healthcare, Automotive and Mobility, Aerospace, Space and Defense, and Software. Each online event focuses on real production deployments, qualification, and supply chain integration. Practitioners interested in contributing can complete the call for speakers form here.
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Featured image shows U.S. Nuclear Regulatory Commission-permitted advanced reactor project currently under nuclear construction in the U.S. Photo via Kairos Power.
