
The work is part of the Specialized Materials and Manufacturing Alliance for Resilient Technologies, or SM²ART.The University of Maine
US scientists have introduced a groundbreaking approach to building nuclear reactor components faster than ever before, using one of the world’s largest 3D printers.
The researchers at the University of Maine’s (UMaine) Advanced Structures and Composites Center (ASCC) utilized the super-sized polymer 3D printer to design enormous, precision-shaped concrete form liners.
These custom liners were built for Kairos Power, a California-based firm designing a next-generation 35-megawatt (MW) nuclear reactor, Hermes. This low-power reactor is under construction in Oak Ridge, Tennessee.
Each wall section of Kairos Power required is three feet thick, 27 feet tall, and shaped in a complex sinusoidal curve.
Printing massive structures
Confronted with a tight deadline and a reactor design demanding millimeter-level precision, Kairos Power turned to the ASCC following a recommendation from the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL).
The firm asked the ASCC researchers to print the longest forms ever produced at the center for casting the massive concrete radiation-shielding wall of the reactors. The forms were then precision-machined to meet tight tolerances.
The facility is home to the world’s largest polymer 3D printer, which is capable of printing hundreds of pounds of material per hour. The team then designed and 3D printed specialized sinusoidal concrete form liners that fit into a steel frame.

The project shows the University of Maine’s role in workforce development.Credit: The University of Maine
The new scanning and metrology team then checked every curve and angle against the digital model to ensure accuracy and quality. “There was no margin for error,” Susan MacKay, ASCC chief sustainable materials officer, pointed out.
The effort resulted in a hybrid casting system that reduced costs, sped up production, and helped Kairos Power keep its high-stakes project on track.
“We met a commercial deadline with massive, high-precision components, a feat that felt astonishing for an academic center,” MacKay continued. “This partnership demonstrates that UMaine’s capability is truly operating at the speed of industry,” MacKay continued.
Advanced printing tech
UMaine said that the work is part of the Specialized Materials and Manufacturing Alliance for Resilient Technologies, also known as SM²ART. The partnership addresses industry challenges and reduces manufacturing costs by leveraging local materials and the advanced production capabilities of the university and ORNL.
Ryan Dehoff, director of DOE’s Manufacturing Demonstration Facility, said UMaine demonstrates how universities and national labs can team up to strengthen US manufacturing. “Partnerships like SM²ART give industry a direct path to the tools and talent needed to build the nation’s next generation of energy and defense infrastructure,” he stated.

Kairos turned to UMaine for an approach that could meet commercial timelines without sacrificing precision.Credit: The University of Maine
In addition to physical printing, UMaine researchers are building digital assurance through the Material Process Property Warehouse (MPPW). The system uses AI and machine learning to record and track every step of large-scale additive and convergent manufacturing.
By creating a digital thread, the MPPW enables components to be born certified, a breakthrough that reduces costs, regulatory delays, and risk for industries such as nuclear energy and defense.
Habib Dagher, ASCC executive director, noted that the 27-year-old center, based in a 150,000-square-foot lab with 400 staff, has a long record of meeting the demanding schedules of private industry.
“It’s an unusual level of performance for an academic institution – and a critical advantage as the U.S. seeks to modernize its energy infrastructure,” he concluded in a press release.
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