September 1, 2016 – In nuclear reactors, energetic neutrons slam into metal atoms that are ordered in a lattice, displacing them with enough force to trigger a cascade of collisions. Laurent Béland, Yury Osetskiy and Roger Stoller, of the Energy Dissipation to Defect Evolution Energy Frontier Research Center at the Department of Energy’s Oak Ridge National Laboratory, modeled radiation damage and discovered that the number of defects ultimately created in a material correlates with atomic displacements that high-pressure shock waves generate early in the collision cascade. “In a typical simulation, the forces emerging from interatomic interactions at these distances are inaccurately modeled, which impacts the final outcome of the cascades,” Béland said. “This region where we had only an ad hoc description of collisions is where all the important things happen,” Stoller added. Their better understanding will improve simulations of chemically complex alloys.
