11/26/2024 Jenny Applequist 5 min read
Written by Jenny Applequist
A multi-institution team led by MechSE’s Janelle Wharry has received $2.5 million from the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) to pursue the design of new materials that could make nuclear fusion power plants a reality. The grant is from ARPA-E’s Creating Hardened And Durable fusion first Wall Incorporating Centralized Knowledge (CHADWICK) program, which aims to explore promising alloy design spaces and manufacturing processes to develop next-generation materials for the “first wall” that surrounds the fusion core of nuclear fusion reactors.
Today’s nuclear power plants produce energy via nuclear fission, wherein atoms are split to release energy. But Wharry—who joined Illinois as a professor just four months ago—explained that fission power has downsides.
“Although it’s considered a green energy, low-carbon source, it’s technically not a renewable source, because of the use of nuclear fuel. And you need to mine uranium to create the fuel... and then you have to dispose of the used fuel,” she said. “And in addition... there are always going to be radioactivity concerns, and general public acceptance concerns.”
In theory, power plants could instead generate energy via nuclear fusion, wherein energy is released by the fusing of atoms. With fusion energy, Wharry explained, “there’s not as much concern with creating radioactive material and exposing the public to it... and it’s just inherently more of a renewable resource, in that you don’t have that same need to mine uranium, and deal with the waste, that you have with fission.”
It’s therefore also less controversial.
So why haven’t we shifted to fusion power? The immensely high temperatures and pressures needed to join nuclei together are a major challenge. Fusion is how the sun generates its energy, and to achieve fusion power generation, something like the sun’s environment would need to be created inside power plants here on Earth—and materials are not yet available that can endure such conditions. That’s where the new project aims to make a difference.
Wharry explained that fusion power plants will have a plasma contained within a massive vessel.
“To contain that plasma, you need materials that are going to be able to withstand really high temperatures as well as radiation and particles from that plasma that are basically slamming up against this containment vessel. And so that’s really the big challenge with making a fusion reactor happen,” she said.
The project aims specifically to create a new class of materials for the “first wall” that will be closest to the plasma.
The team’s novel strategy is to leverage immiscibility, the property that materials share if they naturally separate apart, like oil and water. Engineers have traditionally seen immiscibility as a problem. But for this project, Wharry said, “We’re saying, let’s take the other approach; let’s force materials to not mix together, because after the extreme conditions that a fusion reactor would impose, the material will phase-separate or un-mix anyway. So if we start with an un-mixed material to begin with, maybe that material is essentially more stable in the long term.”
The effort will concentrate on three key aspects of immiscibility. First, immiscible phases are more stable than miscible or mixed solids in the presence of radiation, limiting embrittlement of the material. Second, immiscible interfaces have self-stabilizing properties that resist swelling. Finally, immiscibility opens the door to creation of components that aren’t a uniform material throughout, but instead have a gradient composition with different amounts of various elements at different depths.
Wharry added that for her, one of the exciting aspects of the project is the chance to collaborate with three outstanding Illinois colleagues who have complementary expertise.
“In MechSE, we have me and Professor Huseyin Sehitoglu, who are experts in mechanics of materials and radiation effects, while from the materials department, we have Assistant Professor Marie Charpagne, who is an expert on advanced manufacturing, and Assistant Professor Jean-Charles Stinville, who is an expert on accelerated materials discovery and design. We also have Soumita Mondal, a research scientist in my group, who is an expert on immiscible materials. And so this really is the ideal project, if you will, that brings the five of us together and our strengths and really leverages that, together with the investments that the U. of I. has made in the equipment for manufacturing of these materials as well as characterization at MRL.”
Partner institutions on the effort include the Pacific Northwest National Laboratory, the Electric Power Research Institute and Kyoto Fusioneering.
This award is one of two new CHADWICK grants awarded to Illinois. The other, led by April Novak in the Department of Nuclear, Plasma and Radiological Engineering, will develop an open-source centralized library documenting the radioactivity of materials for potential use in fusion power plants.
Grainger Engineering Affiliations
Marie Charpagne is an Illinois Grainger Engineering assistant professor of materials science and engineering.
April Novak is an Illinois Grainger Engineering assistant professor of nuclear, plasma and radiological engineering.
Huseyin Sehitoglu is an Illinois Grainger Engineering professor of mechanical science and engineering and serves as director of The Fracture Control Program. Sehitoglu holds the John, Alice and Sarah Nyquist Chair affiliation.
Jean-Charles Stinville is an Illinois Grainger Engineering assistant professor of materials science and engineering and is affiliated with the Materials Research Laboratory.
Janelle Wharry is an Illinois Grainger Engineering professor of mechanical science and engineering.