Method for inhibiting corrosion of ferrous materials in freshwater environments

摘要

PROBLEM TO BE SOLVED: To provide a corrosion inhibition method for a ferrous material such as carbon steel constituting a reactor pressure vessel, a reactor containment vessel and various support structures and a cooling water piping and the like of a nuclear power plant which is damaged by a severe accident, an earthquake disaster and the like, the method enabling the risk of corrosion of the whole surface of the ferrous material and through leakage caused by local corrosion of the ferrous material to be prevented, and enabling corrosion to be effectively inhibited over a long period of time, even when fresh water which contains more corrosive ions such as chloride ions and sulfate ions than normal pure water and is in a situation of being exposed to radiation rays is used as cooling water.SOLUTION: A method for inhibiting corrosion of a ferrous material in a fresh water environment is provided in which when a sum of the equivalent weight of chloride ions and sulfate ions contained in the fresh water is 6.2 meq/L or less, pentaboric acid ions are caused to coexist with fresh water in such a way that a sum of the equivalent weight of hydrogen carbonate ions and the pentaboric acid ions becomes 74 meq/L or more.SELECTED DRAWING: Figure 2