The deposition of corrosion product in steam generator inlet of a High Temperature Gas Cooled Reactor (HTGR) is known to occur in regions of the orifice device. In order to effectively inhibit the occurrence of corrosion product deposition on orifice device, a micro-fluidic flow cell was used to recreate accelerated flow under simulated HTGR conditions, by flowing water through a disc with a central micro-orifice. The effect of dissolved oxygen in water on deposition rate was investigated. In particular, the effect of dissolved oxygen on ZETA potential of water containing iron was investigated. The morphology and composition of the depositions were analysed with respect to experimental conditions. The deposition rate of corrosion product was found to be sensitive to dissolved oxygen, and the deposition rate decreased with the increase of dissolved oxygen concentration in water, due to the effect of dissolved oxygen on ZETA potential, suggesting that the electrokinetic effect plays an important role on corrosion product formation in areas of accelerated flow. Increasing the dissolved oxygen in feed water was an effective method to suppress the deposition and clogging of the steam generator orifice device in HTGR.