Materials for Nuclear Reactors (Prof. Szlufarska)

Simulations provide a powerful approach to investigate behavior of materials in extreme environments (e.g., high pressure, high temperature, radiation), such as those encountered in nuclear reactor systems. Prof. Szlufarska’s research in this area involves multiple materials relevant for nuclear applications, such as silicon carbide, graphite, zirconium, and zirconium oxide. For instance, radiation effects of SiC are of great interest to the nuclear industry, because of the existing or potential applications of this material, e.g., as advanced nuclear fuel forms, structural components for fission reactor systems, blanket structures for fusion energy systems, and the immobilization of nuclear waste. Simulations of radiation effects in ceramics are significantly more challenging than in metals because of the more complex electronic structure of ceramics, which in turn leads to a more complex defect energy landscape. Prof. Szlufarska leads a number of joint modeling and experimental efforts in this area aimed at designing materials with superior radiation resistance. For instance, we explore the effects of interfaces on evolution of radiation damage in nanocrystalline ceramics and nanocrystalline ceramic composites. To bridge the different length scales and time scales in simulations, we combine highly accurate ab initiocalculations of small defects, accelerated molecular dynamics simulations of small defect clusters, and rate-theory models of long-term defect evolution. A number of projects in this area are done in collaboration with Prof. Dane Morgan (see nuclear materials).

[18] C. Jiang, N. Swaminathan, D. Morgan, I. Szlufarska, Effect of grain boundary stresses on sink strength, Materials Research Letters, 2, 100-106 (2014)
[19] X. Wang, M. Khafizov, I. Szlufarska, Effect of surface strain on oxygen adsorption on Zr (0001) surface, J. Nucl. Mater. 445, 1-6 (2014)
[20] C. Jiang, M-J. Zheng, D. Morgan, I. Szlufarska, Amorphization driven by defect-induced lattice instability, Phys. Rev. Lett 111, 155501 (2013)
[21]Y. Katoh, L. L. Snead, I. Szlufarska, W. Weber, Radiation effects in SiC for nuclear structural applications, Current Opinion in Solid State & Materials Science, 16, 143-152 (2012)


Fig.7: (Left) Experimental results showing that nanocrystalline (nc) SiC shows enhanced resistance to radiation-induced amorphization, i.e., a higher dose to amorphization than a single crystal SiC. This trend has been attributed to the presence of stacking faults in the nc SiC, as confirmed by our ab initiocalculations. (Right) Clusters of C interstitials in SiC predicted in our atomistic simulations that combine interatomic potentials, ab initio calculations, and structure identification algorithms.