Saheed B. Adisa¹, Matthew J. Swenson¹, Jing Hu²; ¹University of Idaho, ²Argonne National Laboratory

The objective of this study is to evaluate the evolution of Nb-rich nanoclusters in a model Zr-1.0%Nb alloy following irradiation with Kr2+ ions or neutrons to a common dose and temperature. Zirconium-niobium alloys are commonly used as cladding materials for both light and heavy water reactors, and it has been shown that the irradiation induces clustering of Nb. But the mechanism of irradiation-induced Nb clustering in Zr is not fully understood. In this study, an RXA Zr-1.0%Nb alloy was irradiated with Kr2+ or neutrons to a common dose of ~9 dpa (each at 310 °C). The resulting nanoclusters are characterized using atom probe tomography, while the clustering mechanism is modeled using a simple simulation based on rate theory. Following each irradiation, similar Nb-rich cluster morphologies are observed, suggesting charged particles potentially emulate neutron irradiation reasonably well. However, modeling results indicate this emulation may not be accurate at higher doses.