Deposition behaviour of corrosion products on the Zircaloy heat transfer surface

The deposition behaviour of corrosion products on the Zircaloy heat transfer surface was examined under four different experimental environments. First, iron oxide deposition on two kinds of Zircaloy surfaces was carried out in order to evaluate the effects of the oxidation state of Zircaloy. Second, the amount of iron oxide deposits on the Zircaloy surface was measured in order to analyse the influence of dissolved hydrogen. Third, nickel oxide deposition was carried out on two Zircaloy surfaces with dense and porous iron oxide layers, respectively, to evaluate the effects of pre-deposited iron oxides. Finally, the effects of Fe2+ ions on the deposition of iron oxide micro-particles were examined in a suspended hematite solution and a mixed solution containing Fe2+ ions and suspended hematite. In our results, a heat treatment of the Zircaloy surface was effective for reducing the iron oxide deposition. Dissolved hydrogen and Fe2+ were found to promote the deposition of the iron oxides. And the amount of nickel oxide deposits was increased on the porous iron oxide layer.