Oxidative degradation of cation resin in condensate filter demineralizers in Scandinavian BWRs

For several years there has been a trend towards reduced sulfate limits in BWR water chemistry specifications Concurrently with this trend, sulfate levels in some Scandinavian BWRs have become increasingly difficult to control. The mechanism behind the sulfate problems has proven surprisingly difficult to analyze and a full understanding has not yet emerged. This paper presents some of the plant experience, the basic mechanism that is believed to be responsible, and results from an ongoing exploratory investigation designed to study the influence of the most important parameters. (J.P.N.)