Field Experience with KWU SG Chemical Cleaning Process

Abstract

The ingress of corrosion products into PWR steam generators (SG's), their deposition and the subsequent concentration of salt impurities can induce a variety of mechanisms for corrosion attack on SC tubing. Already, some plants have had to replace their steam generators due to severe corrosion damage and others are seriously considering the same costly action in the near future. One of the most effective ways to counteract corrosion mechanisms and thus to reduce the likelihood of SG replacement becoming necessary is to clean the SG's. In this article, the KWU chemical cleaning process, for which there is considerable application experience, will be described. As an example for it's cleaning effectiveness the field applications and their results at Ringhals Units number three and four will be presented.