A Two-Dimensional Transport Model with Phase-Field Method for Pit Propagation Relevant to Nuclear Steam Generators (60)

Abstract

Aggressive anions including chloride, sulfate, and sulfur species with intermediate oxidation states can accumulate on the secondary side of nuclear steam generators, leading to localized corrosion. Due to undercutting of the surrounding surface and interactions with neighboring pits, the evolution of pit morphology is complex and unpredictable, particularly without the aid of a pitting model relevant to the nuclear industry. Thus, this paper focuses on developing a two-dimensional transport model to simulate the propagation of multiple pits. The moving of the corroding surface is modeled using a phase-field method and based on the dissolution kinetics at the surface. The results of two pit simulations show the formation of the perforated pit cover and merging of two pits under galvanostatic conditions without any remeshing scheme, which is an advancement in the 2-D pitting model.