Assessing the factors affecting the water chemistry parameters in the auxiliary water system of a nuclear power plant

Abstract

Cooling towers are used as a final heat sink which cools the reactor auxiliary systems and transfers the heat energy to the atmosphere. The reliability endowed upon the cooling tower operation in a nuclear power plant is considerably high when compared to other power plants since the proper functioning of auxiliary systems is crucial for the decay heat removal from the core. Hence, appropriate chemistry control is mandatory in the operation of cooling towers for corrosion control, scale prevention, and control of biological growth. The operating data and water chemistry parameters like conductivity, turbidity, free residual chlorine, pH, cycles of concentration, chlorides, hardness, and alkalinity are analyzed for a typical nuclear power plant. The effect of the individual water quality parameter is correlated by the Pearson matrix to find its influence on the system water chemistry parameter. It is observed that the build-up of chloride ions in the cooling water is the major contributing factor for the cooling tower feed and bleed operations. The aspect of reducing the feed and bleed operation is analyzed, and suitable modifications are suggested to reduce water consumption.