Hydrogen absorption by Zircaloy-2 has been studied in neutral sodium sulfate solutions using steady-state polarization measurements, electrochemical impedance spectroscopy (EIS), and scanning electrochemical microscopy (SECM). For applied potentials < -1 V (vs. saturated calomel electrode. SCE), water reduction occurs in faults in the passive oxide covering the alloy. For potentials <=-1.3 V-SCE, SECM detects a distribution of reactive locations on the electrode surface. Matched SECM and SEM images of the same electrode surface show more reactive sites to be located in the beta-phase grain boundaries than on the alpha-grains. The reactivity of surface locations was determined using SECM probe approach curves. Secondary phase particles incorporating impurities such as Fe, Ni, and Cr as Zr(Fe, Cr)(2) and Zr-2(Fe, Ni) are particularly reactive spots, which may act as "windows" for hydrogen absorption into the alloy. This claim is supported by the observation that the surface of the alpha-grains remains passive even at potentials as low as -2.0 V-SCE. The need to include a Warburg impedance element in modeling EIS recorded at potentials >=-1.3 V-SCE suggests that H2O reduction is confined to tight flaws in the oxide at grain boundary locations. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.006301jes] All rights reserved.