An improved mesoscopic oxidation model of metals in lead bismuth eutectic Taide Tan, Yitung Chen * , Huajun Chen Department of Mechanical Engineering, University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454027, Las Vegas, NV 89154-4027, United States Received 14 August 2007; received in revised form 9 October 2007; accepted 22 October 2007 Available online 4 December 2007 Abstract The oxidation process of metals in lead bismuth eutectic (LBE) environment is studied at a mesoscopic scale. An improved stochastic cellular automaton model based on an improved Moore neighborhood is proposed to investigate the development of a continuous oxide layer of metals in LBE. The ionization of metal and the oxidation reaction were simulated with consideration of the transport of oxygen along the grain boundaries and the diffusion of metallic ions. The growth of oxide layer in two directions is observed and the volume expansion effect can be realized by changing the volume control parameter. The model was benchmarked with a diffusion process, both with the analytical solution and with the previous work. Significant agreement was reached between the data. The developed model is also mapped with the experimental data from an LBE loop. A parametric study was conducted in order to check the importance of the main explicit parameters of the mesoscopic model. Ó 2007 Elsevier B.V. All rights reserved. PACS: 81.65.Mq; 02.70.c; 07.05.t; 05.00.00; 47.54.Jk; 28.41.Fr Keywords: Mesoscopic; Oxidation; Model; Lead bismuth eutectic; Cellular automaton 1. Introduction Lead bismuth eutectic (LBE) has been determined to be a potential coolant candidate in reactors and accelerator driven systems (ADS) because of its favorable ther- mal–physical and chemical properties [1–3]. However, the corrosiveness of LBE presents a critical obstacle and chal- lenge for safe applications in advanced nuclear reactors and ADS. One of the effective ways to protect the materials is to form and maintain a protective oxide film along the structural material surfaces by active oxygen control tech- nology [3–7]. The corrosion and oxidation of stainless steel in molten lead or LBE have been studied for years [3–11]. The oxide layer structures from experimental results were summa- rized for steels in molten lead and LBE in Refs. [8,11]. Based on the observations, the mechanism of the oxide layer growth of stainless steel in liquid lead and lead alloys were analyzed [8,11]. However, to study such a problem at a microscopic level, such as from an atomic or molecular point of view, has always been a great challenge for the scientists and researchers in the field of fluid mechanics, heat transfer, computational fluid dynamics (CFD), etc. It is difficult and time consuming to study so complex a macroscopic phenomenon at a microscopic level. There is no favorable microscopic theory available to explain and calculate all macroscopic fluid mechanics phenomena as a whole. With the development of modern computers, it becomes possible to simulate a simple fluid problem at a microscopic scale, but still not for such a complex problem in which fluid mechanics, heat transfer, mass transfer, chemical reactions and other phenomenon all are involved. Therefore, to build a mesoscopic model for the oxida- tion of metals in lead or LBE environment will be signifi- cant and beneficial for the future study of oxidation 0927-0256/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.commatsci.2007.10.004 * Corresponding author. Tel.: +1 702 895 1202; fax: +1 702 895 4922. E-mail address: uuchen@nscee.edu (Y. Chen). www.elsevier.com/locate/commatsci Available online at www.sciencedirect.com Computational Materials Science 43 (2008) 251–267