Oak Ridge National Laboratory (ORNL) has won the 2026 SME Aubin Additive Manufacturing Case Study Award for a project applying 3D printing technology to nuclear infrastructure construction. Targeting the long lead times and high costs of nuclear plant construction—where concrete structures (including radiation shielding) account for 60% of project schedule risk—the team used large-format additive manufacturing (LFAM) to produce composite molds for casting shielding systems of Kairos Power’s modular reactor. Traditional steel molds require 6-8 weeks to manufacture and are difficult to modify, whereas the ORNL team completed design, printing, and delivery of reusable composite molds in about two weeks, achieving 1/16-inch precision. The molds withstood the pressure of pouring 12-foot-tall wet concrete and completed four column and three wall panel casting cycles with no quality degradation. This breakthrough is significant for small modular reactors (SMRs), demonstrating that digital manufacturing can meet nuclear-grade standards while reducing construction timelines by weeks, opening new pathways for large-scale application of metal 3D printing in energy infrastructure.