Abstract
Recent advances in chemical cleaning solutions for nuclear power plants have reduced the volume of hazardous waste generated and minimized the impact of cleaning on site schedule and operations. Chemical cleanings are most often utilized in secondary side steam generators to reduce the mass of accumulated deposits, consisting primarily of iron oxides with trace amounts of other metal oxides, for improved thermal performance or mitigation of active corrosion mechanisms as a result of increased deposit loadings. Deposit removal solvents typically consist of a chelating agent combined with other agents such as a strong oxidizer based on the application objectives.
A steam generator chemical cleaning using a simple organic dissolution process was performed in the Fall of 2013. The process was applied to the three steam generators (SGs) in a combination of series and parallel operations using oxalic acid as the primary chelating agent for both iron and copper dissolution. The use of simple organic acids for deposit dissolution enables the solution to be readily decomposed and processed to mitigate the final waste streams for disposal. This paper describes the process application and results as it relates to the mitigation of the environmental impact of the cleaning application.
