Influence of dissolved oxygen concentration on the oxide film formed on Alloy 690 in high temperature water

Influence of later-dissolved oxygen on microstructural changes in oxide films formed on Alloy 690TT in hydrogenated primary water

“…To form such a protective oxide film and to decrease the corrosion rate, a certain hydrogen partial pressure is maintained in primary water to maintain a reducing environment during the nuclear reactor operation. The microstructure and chemical composition of surface oxide films formed on Ni-based alloys in simulated normal hydrogenated primary water containing B and Li have been extensively studied [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. It is widely agreed that an oxide film grown on Alloy 690TT consists of an outer layer containing mixed spinel oxide particles of Ni, Cr, and Fe, and an inner layer containing continuous and compact Cr-rich oxides.…”

Galvanic Corrosion between Alloy 690 and Magnetite in Alkaline Aqueous Solutions

“…Although Alloy 690 shows excellent corrosion resistance in PWR environments, it may suffer from corrosion related degradation in high temperature and pressure water [5][6][7][8][9].…”

The corrosion behavior of Alloy 52 weld metal in cyclic hydrogenated and oxygenated water chemistry in high temperature aqueous environment

“…Only a little work focused on the influence of changing environment in one continuous test on the oxide film character in the open literature [7,9]. However, their works mainly concerned the oxide morphology and composition evolution with changing environment while the variation of protective capability of oxide film formed under such changing environment is still not well understood.…”

“…However, in some circumstances, oxygen could be introduced into primary circuits by adding an aerated water to the systems, or by adding oxygen or H 2 O 2 during the plant shutdown process of PWRs to stabilize the oxide to decrease the release of radioactive species into the coolant. During the last several decades, the effect of dissolved hydrogen (DH) and dissolved oxygen (DO) on the oxide film formed on stainless alloy in high temperature water has been investigated thoroughly and it is found that the morphology/structure and corrosion behavior varied largely with DO [7] and DH [3,6,8].…”

“…It is commonly believed that the water chemistry exerts a significant influence on the oxide film properties and hence the oxidation kinetics [3][4][5][6][7]. The hydrogenated water chemistry has been used to keep a low electrochemical potential in the pressurized water reactor (PWR) water to reduce the SCC susceptibility of the materials.…”