Pitting Corrosion Behavior and Design Improvement for the Welds of Steel Liner of Nuclear Power Plants

The pitting corrosion resistance behaviors of S30403, S32101 and S32205 stainless joints were studied under the condition of boric acid as electrochemical solution with different Cl^- content, temperatures, pH, SO₄^2- and oxygen concentrations. The results show that the S32205 joints were more sensitive to temperature than to Cl^- and SO₄^2-, and pitting corrosion potential (E_b) and repassivation potential (E_r) respectively decreased obviously in critical temperature ranges of T_b0＞60 ℃, 40 ℃<T_r0<60 ℃. The E_b and E_r of S32101 and S30403 were almost the same, which were more sensitive to Cl^- than to the temperature and SO₄^2-. The pitting corrosion potential and repassivation potential of S32205 joints were more sensitive to oxygew content than those of S30403 and S32101 joints. The change rule of temperature effect on pitting corrosion potential for joints were basically the same for base materials.