Sougata Roy is leading a project to explore new ways to process tungsten for use in nuclear reactors. Larger photo. Photos by Christopher Gannon.
AMES, Iowa – Sougata Roy, who doesn't study electrons or grids or wind turbines, has found a way to contribute to a clean-energy future.
"This work in advanced manufacturing, particularly in using additive manufacturing, is about making a difference," said Roy, an Iowa State University assistant professor of mechanical engineering and a Building a World of Difference Faculty Fellow in Engineering.
Roy has a new four-year, $1 million grant from the U.S. Department of Energy to study the possibilities of using additive manufacturing, known as 3D printing, to create shields and components that could be used in nuclear reactors.
"One of the major things that excites me about this project is working with nuclear energy," Roy said. "It's the largest source of clean power in the United States. This emission-free electricity is important for the future."
(The U.S. Energy Information Administration reports that the U.S. produces about 19% of its electricity from nuclear power. About 10% comes from the country's wind turbines.)
The grant will allow Roy, as the lead researcher, to assemble what he calls a DREAM-TEAM project: "Developing a Robust Ecosystem for Additive Manufacturing of Tungsten for Extreme Applications and Management."
Joining Roy on the project are Yachao Wang, an assistant professor of mechanical engineering at the University of North Dakota, and researchers from three of the U.S. Department of Energy's labs: Ames National Laboratory on the Iowa State campus, Argonne National Laboratory in Illinois and Oak Ridge National Laboratory in Tennessee.
The grant is part of a $36 million effort by the energy department's Established Program to Stimulate Competitive Research (known as EPSCoR). The program is designed to build energy-related research capabilities and expertise across the country.
The researchers will work with tungsten, a top material candidate for the inner walls of fusion reactors because it maintains strength at high temperatures, has a high melting temperature, resists erosion under high-energy neutron irradiation and retains low levels of radioactive tritium.
But, Roy said, tungsten is expensive for conventional manufacturers to work with because it's hard and brittle.
So, the researchers asked, what if we try unconventional processing?
They'll try 3D printing tungsten-based alloys using technology known as laser powder-blown directed-energy deposition. It involves using a laser under oxygen-controlled conditions to process tungsten powder and, layer by layer, print the metal.
Roy, who has experience 3D printing other steel-based alloys for nuclear energy applications, said the project will allow him to purchase a new instrument to characterize the mechanical properties (including the instrumented indentation characteristics and the fracture toughness) of the printed samples.
Roy said the most unique part of the project isn't the actual printing, it's the physics-based modeling and computational simulations of the printing process that will complement the experimental work.
The modeling and simulations, which will include work with machine learning and artificial intelligence tools, will help researchers establish the theories behind their experimental results. The simulations will also help them develop recipes for tungsten alloys that can withstand the extreme conditions inside a nuclear reactor.
"We'll start with pure tungsten," he said. "Eventually we'll develop new alloys to resolve this cracking challenge."
Roy puts the emphasis on the "we" when he talks about the project and its goals.
"This is a real DREAM-TEAM," he said, "nothing like this project can be done alone."
