[3E09-12] Corrosion Potential, Zinc Injection

[3E10] The effects of hydrogen addition on the corrosive conditions of PWR primary coolant under irradiation

(7)Comparison of ECPs of stainless steel and Ni base alloy

*Shunsuke Uchida¹, Kuniki Hata¹, Satoshi Hanawa¹, Yasuhiro Chimi¹ (1. JAEA)

Keywords:PWR, water radiolysis, ECP analysis, stainless steel, Ni base alloy

Stainless steel (Fe base alloy) and Ni base alloy are different in anodic polarization curves in high temperature water, which results in different ECP under the same water chemistry conditions. Based on analysis of the effects of temperature and pH on solubilities of Fe²⁺ and Ni²⁺, the effects of radiolytic species, H₂O₂, O₂ and H₂, on ECP are analyzed. As a result of the analysis, Ni base alloy showed a little lower ECP than that of stainless steel, and its pH dependence was different from that of stainless steel. The ECPs in the core, its peripherals and SG were analyzed based on radiolytic specie concentrations shown in the previous presentation, which were applied to evaluation of the hydrogen injection effects on the major component in the primary cooling system.