Argonne Proposes an ASME Code Pathway for 3D-Printed Nuclear Reactor Parts

A regulatory roadblock gets a proposed detour

Argonne National Laboratory has submitted a proposal to the American Society of Mechanical Engineers that could finally give laser powder bed fusion a formal role in nuclear reactor manufacturing. Right now, the process sits outside most nuclear codes. That makes it nearly impossible for reactor builders to specify 3D-printed metal parts even when the printed version outperforms a forged or cast alternative. Argonne wants to change that.

The proposal was developed with Oak Ridge, Idaho, and Los Alamos national laboratories. It pairs real-time process monitoring with AI-driven analytics to build a complete digital record of each printed component. The goal is not to relax standards. It is to prove that in-process data can be as trustworthy as the destructive tests regulators have relied on for decades.

Why LPBF needs its own rulebook

Laser powder bed fusion builds metal parts one thin layer at a time. It can produce shapes that no forge or mill can match, with internal channels and lattice structures that improve heat transfer. But nuclear codes were written around wrought and forged materials. A printed part is both material and component at once, so traditional qualification methods do not fit cleanly.

Argonne's approach treats the printing process itself as part of the qualification. Sensors watch melt pool behavior, layer geometry, and thermal history. Machine-learning models flag anomalies as they happen. The result is a birth certificate for the part that includes every second of its manufacture, not just a final inspection report.

It connects to a bigger federal push

The proposal sits inside the Department of Energy's Genesis Mission, which links national labs, datasets, and computing power to accelerate advanced manufacturing. That same mission is funding INL's Prometheus AI initiative and ORNL's Peregrine defect-detection software, both aimed at making printed nuclear components born-qualified.

ORNL and INL are already working on a parallel track for wire-arc pressure vessels. Argonne's ASME submission covers laser powder bed fusion, a different technology with different applications inside a reactor. Together, the two efforts could cover much of the printed-metal landscape nuclear builders care about.

What happens next

ASME will now review the proposal through its standard consensus process. That takes time, and the nuclear industry is not famous for moving fast. But the submission itself matters. It means U.S. labs are no longer just demonstrating printed nuclear parts in isolation. They are trying to create the rules that let those parts actually be used.

If the pathway is adopted, reactor designers could specify LPBF components with the same confidence they now have in forgings. That would open the door to printed fuel brackets, heat exchanger parts, and structural components that are lighter, more efficient, and faster to produce. For an industry facing a supply-chain crunch, that is a big deal.