October 11, 2006
Journal Article

Molecular Dynamics Simulation of Energetic Uranium Recoil Damage in Zircon

Abstract

Defect production and amorphisation due to energetic uranium recoils in zircon (ZrSiO4), which is a promising ceramic nuclear waste form, is studied using molecular dynamics simulations with a partial charge model. An algorithm that distinguishes between undamaged crystal, crystalline defects and amorphous regions is used to develop a fundamental understanding of the primary damage state. The amorphous cascade core is separated from the surrounding crystal by a defect-rich region. Small, chemically inhomogeneous amorphous clusters are also produced around the core. The amorphous regions consist of under-coordinated Zr and polymerised Si leading to amorphisation and phase separation on a nanometer scale into Zr- and Si-rich regions. This separation could play an important role in the experimentally observed formation of nanoscale ZrO2 in ZrSiO4 irradiated at elevated temperatures.

Revised: January 10, 2007 | Published: October 11, 2006

Citation

Devanathan R., L.R. Corrales, W.J. Weber, A. Chartier, and C. Meis. 2006. Molecular Dynamics Simulation of Energetic Uranium Recoil Damage in Zircon. Molecular Simulation 32, no. 12-13:1069-1077. PNNL-SA-50764.