Evaluation and mitigation of the degradation by corrosion in the components of the service water system of a nuclear power plant

One of the main problems that face the nuclear power stations is the degradation by corrosion in the service water systems. The corrosion causes lost substantial in energy generation and a high cost in maintenance and repairs. In this work, the results of a study of the degradation by the MIC mechanisms (microorganisms influenced corrosion), incrustations in heat exchangers and erosion for solid particles in the components of a typical service water system of a nuclear plant are presented. Diverse mitigation options are analyzed for these mechanisms. In the analysis, it was used the CHECWORKS-CWA code to carry out the evaluation of the degradation so much as well as the mitigation of the caused damage. The results are presented in susceptibility indexes and degradation rates component-by-component. A significant decrement could be observed in the susceptibility to MIC when changing the operation conditions of stagnated flow to continuous flow. With respect to the erosion by solid particles, it was found a significant reduction of the damage it when adding filters to the system. Finally, in the case of the heat exchangers, it is shown that one of the more viable options to diminish incrustations and existent calcium deposits it is the reduction of the pH of the service water. (Author)