Frontier is an exascale computer planned for delivery at the Oak Ridge Leadership Computing Facility in 2021. The system will support a wide range of scientific applications for advanced modeling and simulation, as well as high-performance data analytics and artificial intelligence. In the “Science at Exascale” Q&A series, researchers working on these next-generation scientific applications discuss what they hope to achieve on Frontier.

The Exascale Atomistics for Accuracy, Length, and Time (EXAALT) project focuses on developing atomistic-level simulation capabilities for fusion and fission energy materials challenges, including extending the burnup of nuclear fuel in fission reactors and developing plasma-facing materials that can withstand the harsh conditions inside fusion reactors.

Scientists working in EXAALT aim to simulate the motion of individual atoms in materials and the timescales in which they evolve. Through simulations, scientists are able to trace the evolution of materials at various temperatures, pressures, and exposures to radiation, tracking how they react based on the behavior of their atoms at the nanoscale.

EXAALT is developing a capability for screening materials within a wide range of length and time scales, which has the potential to shrink the design cycle significantly. By integrating high-performance computing with the design loop, scientists can more easily develop lighter alloys, build lighter cars, and design high-temperature-withstanding materials for power plants. Exascale simulations on systems such as the US Department of Energy‘s Frontier will allow for better predictions about the long-time behavior of these systems, leading to better materials, higher vehicle efficiency, and safer power plants.

In this interview Danny Perez, principal investigator for EXAALT as part of the Exascale Computing Project, talked about how exascale systems like Frontier will be able to help scientists discover the complex ways in which materials evolve.

So you’re working on a project involving molecular dynamics simulations and applying those to fusion and fission reactor materials. Tell me about how these simulations help you understand what’s going on in these kinds of reactors.

Perez: We have two problems that drive us. One is in the materials used for fission reactors—the reactors in which uranium dioxide is burned—and the other is in materials used for future fusion reactors, which will produce energy in a similar way as the sun. We want to be able to use our simulations to design better materials for these reactors—or at least understand how these materials age and how they change as they’re exposed to extreme conditions.

How might this kind of research impact the design of new materials?

Perez: If someone comes up with a set of characteristics they’d like a material to have—light, strong, or cheap—it is very time-consuming to come up with a new and improved material. There are many different parameters that you can imagine changing, and that makes this process slow and expensive. We would like to virtually screen materials so we can guide the direction of material design and shorten the design cycle significantly.

Are there certain milestones you expect to see in your science at exascale?

Perez: If you download a code off the web and use the biggest machine you can get your hands on right now, you’re stuck simulating microseconds on very cheap models. Using a combination of advanced methods and scalable codes on Frontier, we’ll be able to perform simulations with potential millionfold increases in our time scales. We’ll also be able to do one-to-one comparisons with experiments and make better predictions about the evolution of these systems.

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