Nuclear fusion, a process akin to the energy production in the sun and stars, holds promise for generating electricity on Earth without carbon emissions or long-lasting nuclear waste. The success of this technology depends heavily on developing materials that can endure extreme conditions such as high temperatures, mechanical stress, and neutron damage. Researchers are exploring novel metal alloys and ceramic composites to enhance fusion reactor designs.
David Sprouster, an assistant professor at Stony Brook University's Department of Materials Science and Chemical Engineering, is leading several research projects focused on overcoming the challenges associated with new materials for fusion energy. "My research is really about stress testing these different materials to see how we can improve their function when exposed to different combinations of extremes," Sprouster stated. He added that designing and fabricating these materials in the lab is both challenging and enjoyable.
Sprouster's team has secured three multi-million dollar grants targeting materials for fusion energy, including two from the Department of Energy's Office of Fusion Energy Sciences Fusion Innovation Research Engine (FIRE) Collaboratives.
In one study, Sprouster's group examined two steels with similar alloy compositions but fabricated differently: one through traditional casting and the other via direct current sintering. This latter method uses heat and pressure to rapidly form powders into solid materials, allowing complex structures suitable for fusion chamber walls. Both steels were designed to resist deformation over time under heat and stress, a phenomenon known as "creep."
"Creep is a very slow process — it happens over days, weeks, months and years — and depends on the applied stress and temperature," explained Sprouster. His team found that both conventionally cast and sintered materials showed good creep resistance but noted increased susceptibility to deformation at higher temperatures due to easier dislocation movement.
In another study, composites of steel with hafnium hydride were fabricated through direct current sintering for neutron shielding in advanced nuclear fusion reactors. "The hydrogen is there to stop the neutrons," said Sprouster. The study revealed that heating causes hafnium hydride to release hydrogen slowly at higher temperatures than expected in reactor applications.
These studies aim to develop safer, more efficient materials for future fusion reactors operating under extreme conditions. Lance Snead, a research professor at Stony Brook University, highlighted the growing interest in fusion research: "Historically, the Department of Energy was the primary agency funding this future energy source, but with the realization that fusion can be a near-term source of electricity, private investors now dominate the field."
"Fusion is very exciting right now," said Sprouster. He noted significant collaboration among universities, national labs, and industry focused on solving engineering problems through material science solutions.
"Last year over 1.6 billion dollars in private research funding went into fusion," Snead mentioned. As developing robust fusion chamber materials remains crucial for current concepts' success, Professor Sprouster's group finds itself well-positioned in this burgeoning research area.
Future efforts at Stony Brook University's Department of Materials Science and Chemical Engineering will continue advancing materials capable of withstanding fusion's extreme environments.
— Angelina Livigni