The Influence of Dissolved Oxygen Concentration on the Corrosion Resistance of 316L Stainless Steel under Simulated BWR Primary Circuit Water Environment

Abstract

Austenitic stainless steels have been widely applied in the primary circuit of BWR. However, the corrosion caused serious damage to the equipment, affecting the service life of the plant, and lead to many security and economic danger. The oxide film generating on metal surface can slow down the corrosion rate in certain water chemical environment. Researches have shown that the concentration of dissolved oxygen is one of the important factors that affect corrosion resistance of the oxide film. This issue by simulating BWR primary circuit operating mode and controlling the concentration of dissolved oxygen in water solution, studied the corrosion of stainless steel in the autoclave to evaluate the effects of dissolved oxygen on corrosion. Experiments with 316L stainless steel as raw material, after forming an oxide film corrosion experiment, potentiodynamic scanning method and Mott-Schottky plot method were employed to discuss the performance of the stainless steel surface oxidation film. The potentiodynamic polarization curve results indicated that under the dissolved oxygen concentration of 0.28 mg/L and 8.20 mg/L, their current densities of oxidation film were close and significantly less than 0.50 mg/L. Mott-Schottky plot results indicated that under the dissolved oxygen of 8.20 mg/L the carrier concentration of oxide film was the lowest and the corrosion resistance remained its best performance.