Oxygen transport in an LSM/YSZ/LaAlO solid oxide fuel cell type reactor was studied. The oxygen permeation flux was 8.90 x 10(-8) mol m(-2) s(-1) at 1173K with an activation energy of 170 kJmol(-1). By applying an external potential, the oxygen permeation flux increased while the activation energy of oxygen permeation decreased. The oxygen permeation fluxes under methane feed in the anode side are 1-2 orders of magnitude higher than those under helium feed. A model of oxygen permeation was presented and the permeation parameters were proposed. In the case of helium feed, the oxygen permeation at the LaAlO anode was the rate-limiting step. However, changing helium to methane as a reactive gas, the resistances for the oxygen permeation in the three parts (LSM/YSZ/LaAlO) were comparable. (C) 2004 Elsevier B.V. All rights reserved.