Scientists at Oak Ridge National Laboratory (ORNL) and A.J. Tuck Company have developed a new manufacturing technique that could make it easier and faster to produce important components for advanced nuclear reactors.
The approach combines 3D printing with a process called electroforming to manufacture complex, leak-free containers known as hot isostatic pressing, or HIP, cans.
These containers play an important role in producing strong metal components from powdered materials using intense heat and pressure.
The technology could help address a major challenge facing the U.S. nuclear industry: limited domestic capacity to manufacture large and complicated metal components.
Traditional forging and casting often require enormous specialized facilities, expensive equipment and long production times. Much of this manufacturing capacity is now located outside the United States.
The new technique offers a potentially simpler alternative.
The process begins by 3D-printing a polymer form in the shape required for the component. Because the form is made from plastic rather than metal, complicated shapes can be produced relatively quickly and inexpensively.
The printed form is then placed in a liquid chemical bath. Using electricity, a process called electroforming gradually deposits nickel over its surface, creating a dense and highly accurate metal shell about 2 to 3 millimeters thick.
Researchers then remove the plastic form, leaving behind a hollow nickel container. This container can be filled with metal powder, sealed and placed through the HIP process. High temperatures and pressure cause the powder particles to fuse together, creating a fully solid metal component.
Researchers say the technique has several advantages. Printing the initial form from polymer avoids some of the distortion and material stresses associated with directly 3D-printing metal at extremely high temperatures. It can also reduce equipment and material costs while making it easier to modify designs.
Electroforming can reproduce detailed shapes with high precision and may also be relatively easy to scale. According to ORNL mechanical engineer Amiee Jackson, production time depends largely on the required thickness of the metal coating rather than the overall size of the component. Multiple components could potentially be manufactured together.
During the first phase of the project, researchers successfully produced five leak-free cylindrical HIP cans measuring about 15 centimeters tall and 10 centimeters across. They also created an integrated port that removes the need to separately weld process tubes onto the container. These welds can sometimes become failure points during manufacturing.
The researchers are now testing the technique on more complicated shapes, including an impeller used to move liquids through pumps and turbines or a valve relevant to nuclear systems.
Potential applications extend beyond HIP cans. The technology could eventually contribute to manufacturing large, precise components for reactor pressure vessels, valves, turbines and other energy systems.
With interest in advanced nuclear reactors and small modular reactors growing, the researchers believe faster and more flexible manufacturing methods could become increasingly important. The technology could ultimately strengthen domestic production while reducing dependence on overseas supply chains.
An invention disclosure and provisional patent have been filed for the new approach.
