ORNL's Manufacturing Demonstration Facility says 3D-printed molds are speeding reactor construction

Oak Ridge National Laboratory's Manufacturing Demonstration Facility (MDF) described using large-format additive manufacturing to accelerate construction timelines for advanced reactors on a recent ORNL podcast.

Ryan Dayhoff, who leads MDF, said the facility's work shifted 3D printing from prototyping to production-scale components. He described printers as large as 20 to 30 feet and said MDF worked with industry partners to print precise molds for a reactor bioshield, then poured concrete into a printed mold within two weeks after receiving DOE approval. "Within two weeks, we had a mold, which we never had before, and then to go from a mold that we never had before to an actual column within their bioshield and do that in months," Dayhoff said.

The episode described modular construction using interlocking concrete blocks, some up to 30 feet long, cast from printed molds. MDF leaders said modular blocks can speed onsite assembly and improve geometric accuracy compared with traditional steel or timber molds. Dayhoff also noted a collaboration with the University of Maine, which has one of the largest printer systems in the world, enabling co-development of large-scale printing capabilities.

Podcast participants cited an industry precedent: in 2021, ORNL worked with Framatome and the Tennessee Valley Authority to 3D-print four fuel-assembly brackets that were installed at the Browns Ferry nuclear plant in Alabama. The hosts described that placement as the first time 3D-printed components were installed in a commercial U.S. nuclear reactor.

Dayhoff said MDF is exploring more ambitious metal work, including the potential to produce pressure vessels domestically for large reactors, and he singled out ORNL's High Flux Isotope Reactor (HFIR) as a potential demonstration case if DOE and regulators permit it. He acknowledged that the U.S. currently sources many large pressure vessels from overseas but said smaller vessels can be fabricated in the U.S. today.

MDF officials and industry guests framed advanced manufacturing as a critical enabler to shorten construction timelines and reduce financing burdens: "If you can shrink the timeline, you completely change how things are manufactured and accelerate the cost," one guest said. They cautioned, however, that scaling to mass production and meeting rigorous NRC qualification and safety standards remain key hurdles.

The podcast did not present new NRC approvals or specific contract awards; it described research partnerships, pilot components already installed in commercial reactors, and aspirational goals for domestic pressure-vessel fabrication.