AM Will Change Power Generation, But Needs To Prove Itself First

Additive manufacturing is going to bring new possibilities to power generation systems. Complex 3D printed component geometries promise to deliver both increased power efficiency and reduced manufacturing cost. But when it comes to the kinds of systems that provide safe, reliable power to communities and industrial facilities, AM is being asked to deliver on the old possibilities first. In two different applications — involving gas turbines and nuclear power — Oak Ridge National Laboratory’s Manufacturing Demonstration Facility (MDF) has produced 3D printed components to conventionally manufactured part designs and specifications, so these components can prove their effectiveness for established uses before AM is leveraged to pursue design changes.

The gas turbine application is a collaboration with turbine manufacturer Solar Turbines. The MDF manufactured nearly 300 turbine blades through electron beam melting on machines from Arcam (GE Additive) for evaluation in Solar Turbines’ test platform. The blade design is conventional, including the established material: Inconel 738. The alloy is challenging to 3D print, necessitating the high temperature of EBM. Future turbine blades designed for AM presumably might use a different alloy.

For nuclear power, Oak Ridge partnered with nuclear power industry manufacturer Framatome to make a set of 316 stainless steel brackets through laser powder bed fusion on a machine from Concept Laser (also GE Additive). The brackets help to secure a nuclear fuel assembly within the Browns Ferry nuclear power plant in Alabama. Their evaluation will come in 2027, after they have operated for six years, when the brackets will be removed and sent back to Oak Ridge for examination.

The fundamental question in both cases is: Can power-system OEMs be assured that metal parts made via additive manufacturing are just as reliable and stable as metal parts made through the production processes we are used to?

The long-term promise justifies the exploration. Oak Ridge Research Materials Scientist Mike Kirka has been involved in the turbine blade work. With AM, he says, turbine makers will be able to “open up new design paradigms for more efficient cooling schemes that would allow turbine blades in the hot section of the engine to run much hotter while being [internally] cooled. This would have multiple impacts, from the energy efficiency of the engines themselves to potentially more resilient components with longer service lives.”

Deposition Science and Technology Group Leader Ryan Dehoff of Oak Ridge worked on the nuclear bracket. “A nuclear reactor is essentially a very large-scale heat exchanger. Additive enables us to print very complex designs,” he says, for more effective heat transfer. “I think that there could be a very large impact from additive manufacturing technologies inside the nuclear industry. The challenge is we have to certify and qualify the components.”