Chloride Ingress Protection System Reliability Assessment

CRA were tasked by a client to perform a reliability assessment of the chloride ingress protection system installed at their power plant to confirm it met the latest safety requirements.

At power plants, chlorides, usually in the form of seawater, can cause significant damage to the stainless steel sections of boilers due to a process known as stress corrosion cracking. Since seawater is often used to cool the condenser that supplies the boilers, there is a risk of a chloride ingress event if there is a condenser tube leakage. Chloride ingress protection systems are used to identify such an event and automatically isolate the feed to the boilers if it should occur.

The protection system consists of three probes measuring conductivity levels in the water to the boilers. Each probe is connected to an individual conductivity monitors that compares the conductivity levels in the water against a set trip-point. Signals are sent to close the isolation valves if two-out-of-three (2oo3) conductivity monitors detect high levels of conductivity (due to a chloride ingress event).