Study on Stress Corrosion Cracking Susceptibility of 316LN in Simulated Primary Loop of PWR Under Abnormal Water Chemistry Conditions

It was studied that the effects of chloride ions and dissolved oxygen on stress corrosion cracking (SCC) behavior of 316LN stainless steel in simulated primary loop of pressure water reactor (PWR) under abnormal water chemistry conditions with slow strain rate test (SSRT) method. The results show that in saturated oxygen condition, the extension of specimens decreases gradually while the SCC sensitive index increases with the increase of chloride ions concentration. In addition, the samples will produce SCC in the case that the concentration of chloride ions is more than 1 mg/L. However, cracks are not initiated in de-aerated solution even if the concentration of chloride ions increases to 10 mg/L. The stress corrosion cracks of 316LN are initiated in defects or Cr-depleted zones at the surface and transgranularly propagates into the base metal.