In this study we employed the ReaxFF reactive force field to examine the dynamics associated with the dissociation of adsorbed water molecules on an aluminum nanocluster surface. We have investigated several different concentrations of water on an Al-100 cluster to elucidate the dynamics of the dissociation phenomena. Our results indicate that the dissociation of an isolated water molecule on the surface requires significant activation energy, and that an assisted dissociation by a neighboring, non-adsorbed, water molecule is more energetically favorable. The dynamics of this reaction pathway are discussed and compared to recent quantum studies along with a further investigation of the role inert gases and oxide layers have on these processes. Our results shed light on this atomic scale behavior and increase the potential for reactive metal/water systems to be used as lightweight, portable, and on-demand energy sources via fast hydrogen gas production. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.