Establishing the Root Cause of a Failure in Condenser Tubes in a Power Plant

This paper investigates the root cause analysis of a failure in brass tubes in a power plant condenser unit. Condenser tubes in power plants are plugged in when a leakage is detected and spotted on-site. Plugging means fewer available tubes in a condenser, which clearly has negative implications for the efficiency of the heat transfer between the cooling water and passing-through steam, coming from the turbine. At some point, when the number of pipes with leakages reaches a critical threshold, the condenser needs to go through a total re-tubing, which is a rather large investment. It is therefore extremely imperative to understand the governing degrading mechanisms in condenser tubes to extend the lifetime of condenser units. This paper presents a systematic investigation of a failure in condenser tubes in a power plant. A comprehensive microstructural analysis was carried out to come up with the dominant failure mechanism. Results showed that de-alloying and more specifically dezincification have the most prominent attribution to the failure of condenser tubes in this plant. The inter-relations between process parameters, the microstructure and degradation mechanisms are discussed.