ORNL and INL Use Wire Arc 3D Printing to Make Nuclear Pressure Vessels at Scale

A three-robot arm printer just built a full-scale nuclear pressure vessel

The Department of Energy's Oak Ridge and Idaho national laboratories are collaborating to produce large industrial pressure vessels using wire arc 3D printing, a move aimed at strengthening domestic supply chains for nuclear energy. The partnership was announced August 19 at Oak Ridge's Materials and Manufacturing Innovation Days event.

Pressure vessels sit at the heart of nuclear reactors, steam systems, and chemical plants. They are traditionally forged, a process that requires heavy tooling, long lead times, and specialized domestic capacity that is currently stretched thin. Wire arc additive manufacturing melts metal wire into layers, building near-net-shape parts that need less machining and no custom tooling.

In July, Oak Ridge researchers used their Medusa platform to print a demonstration pressure vessel roughly three feet by five feet from a steel alloy relevant to nuclear applications. Medusa coordinates three robotic arms that melt wire with electric arcs, and it produced a large closed vessel with a domed shape in a single build. That proved the technology can scale beyond small coupons to real industrial components.

AI inspection built into the build

The next step is qualification. Nuclear regulators do not approve parts because they look good on a scanner after printing. They need data showing the material is sound throughout. Oak Ridge and Idaho are building AI-driven inspection directly into the printing process so that shape, density, and microstructure can be verified in real time instead of after the fact.

"We want to achieve born-qualified pressure vessel components using data gathered during printing to confidently assess their worthiness for extreme environments," said Patxi Fernandez-Zelaia, the Oak Ridge lead researcher. The goal is to shorten the qualification timeline from years to months.

Idaho National Laboratory brings decades of nuclear reactor experience, including recent advanced-reactor criticality achievements and the Prometheus project, which applies AI to digital engineering for nuclear systems. Combining Idaho's material-property expertise with Oak Ridge's additive manufacturing capability gives industry a single pathway from prototype to certified part.

The same Medusa platform already printed neutron sensor brackets for Antares Nuclear's R1 Mark-0 microreactor, which reached criticality at Idaho in June. That project served as a practical test of the printer and the AI inspection tools before scaling to pressure vessels.

If wire arc printing can produce certified nuclear pressure vessels on demand, the impact goes beyond reactors. The same approach could serve chemical refining, oil and gas, defense, and aerospace. The laboratories frame it as a domestic resilience play: fewer imported forgings, shorter repair cycles, and a manufacturing base that can respond to disruptions instead of depending on long supplier queues.