Effects of Hydrogen Peroxide on Intergranular Stress Corrosion Cracking of Stainless Steel in High Temperature Water, (II)

Abstract

In order to determine a crack propagation rate of less than 10^-8 mm/s in a 24-hour integrated measurement, major parameters of a coupled system of a constant tension specimen and crack depth measurement, based on potential drop method, have been optimized. Influences of sensor geometry, location for detecting potential drop and data processing of the ratio of signal to noise (S/N) were optimized by applying Taguchi's Method. Then a suitable sensor geometry and data processing method were proposed to get a robust measurement system with higher sensitivity and lower susceptibility for geometrical and procedural fluctuations.

By applying the optimal crack propagation rate measurement system, it was confirmed that a crack propagation rate of lxlO^-8 mm/s can be measured under a low concentration condition of hydrogen peroxide with less than a 20% error by a 24-hour integrated measurement.

KEYWORDS:

• BWR type reactors
• water chemistry
• stress corrosion
• cracking
• stainless steel
• potential drop method
• cracks
• crack propagation rate
• electrochemical corrosion potential
• robustness
• hydrogen peroxide
• measuring methods
• errors
• reliability
• S/N ratio
• temperature dependence
• temperature coefficient