Inferring local chemistry from thermal hydraulic and electrochemical monitoring

An integrated scientific approach can be successful in identifying crack mechanisms and likely causative environments for the cracking problems occurring in Alloy 600 tubing. A complete understanding of the phenomenon requires an additional link between the laboratory data and plant heat exchanger performance. This paper describes how simple thermocouple based electrochemical probes can be used to interrogate the chemistry in occluded regions where the cracking might occur. MULTEQ is used to help interpret the resulting data by providing high temperature pH and boiling point elevation calculations. The use of these probes can also provide insight into how the local environment changes with time