As critical materials used in many advanced nuclear reactors, nickel-based alloys often come with some unwanted baggage, according to researchers at the Argonne National Laboratory (Lemont, Illinois, USA) of the U.S. Department of Energy (DOE).
Aside from being very expensive, nickel ore is mined in politically sensitive parts of the world. The ore also has a high moisture content that can pose safety issues for those transporting it in cargo ships, since the cargo can slosh around and create a load imbalance.
Despite nickel’s comparable strength and several notable advantages over steel—including heavy resistance to corrosion and a structure that can withstand the harsh environments inside nuclear reactors—scientists would like to discover alternate materials.
Accelerating New Materials Discovery
With that in mind, Argonne’s nuclear science and technology experts have worked for the past two years to develop a framework to accelerate the discovery of new nuclear reactor-appropriate materials. These new materials could be used in place of critical minerals like nickel alloys.
As Argonne explains, the discovery of appropriate new materials is crucial and can advance the development of next-generation nuclear power, which is central to efforts by the United States to produce clean energy and meet decarbonization goals.
“It takes a very complex procedure to demonstrate and qualify a coating for use in a nuclear reactor,” says Yinbin Miao, an Argonne principal materials scientist and lead investigator on the research team.
“By using a multi-physics model informed by experimental measurement, we have more insights on different aspects of the problem,” Miao adds. “That’s helping us find the optimized recipe or thickness of different layers that use nickel alloys. It helps us understand what material composition will be needed so we have a model to accelerate optimization speed.”
How the Researchers Work Together
Miao has experience in multi-physics simulation of nuclear systems and material performance analysis under harsh conditions in nuclear reactors.
Sumit Bhattacharya, also a principal materials scientist, is a coating expert for extreme environment applications. His focus is on identifying advanced material coating architecture, and specifically its development and optimization for complex designs.
Ed Hoffman, a principal nuclear engineer, models the techno-economic benefits of each new material and how each does or does not affect reliance on critical materials.
Ahmed Amin Abdelhameed, a nuclear engineer, is an expert in neutronics and studies changes in a reactor’s performance based on the behavior of materials studied in the experiments.
Additionally, postdoctoral researcher Soon Kyu Lee helps the team with modeling and Wei-Ying Chen—another Argonne principal materials scientist with expertise in materials characterization—helps measure some key coating properties needed for simulations.
“Previously, we’d do a test that reveals a material is not good enough, then we’d change some parameters and eventually get a more optimal solution,” Miao says. “With this new framework, we have more input from multi-physics simulations to make sure each iteration gives enough improvement. We make sure each change would be beneficial and that helps us speed up the optimization procedure.”
Searching for Corrosion Resistance
A key quality the team looks for in candidate materials is corrosion resistance. This quality is needed because the environment inside a nuclear reactor is one of intense radiation and very high temperatures. Material coatings must possess mechanical strength, but they also need to demonstrate resistance to corrosion during both normal operations and accident scenarios.
To study corrosion resistance and the material strength of one promising material, the team used a new capability at the Argonne Tandem Linac Accelerator System (ATLAS), which is a DOE Office of Science user facility.
In this research, they bombarded their target with heavy ions to simulate the high-radiation conditions inside a reactor. The new ATLAS Materials Irradiation Station degraded the material’s properties as much in a day as a nuclear reactor does in a year, minus the long-lasting radioactivity.
Ultimately, they demonstrated that the new material could indeed withstand reactor conditions and resist corrosion. “We wanted to build a framework that works for different coatings but we also needed to provide a demonstration case,” Miao says. “Otherwise, it was just a framework example without any demonstration.”
Going forward, the team plans to file a patent for the new coating material, and it is currently seeking more funding to further investigate its properties. Thus far, the project has been funded by Argonne’s Laboratory Directed Research and Development program.
Source: Argonne National Laboratory, www.anl.gov.