Chemical Feed System (or Chemical Dosing System) is a facility for injecting various types of chemicals into water cycling circuit in the exact amount that is needed to control the water chemistry within required limits. If a chemical feed system were not properly designed and operated, chemistry of water cycle could not meet the specifications which would result in high operating cost, reduced throughput, high corrosion rate and resultant early equipment failure and increased maintenance cost. Design of chemical feed system can vary depending on the plant type, chemicals to be fed, chemistry requirements and control strategy. In general, this system is being operated in conjunction with the steam and water sample handling system so that the chemistry information from sample handling system should be the base for chemical feed control either in automatic mode or in manual.