[en] Almost 30 years of operating experience with PWR nuclear power plants have shown that corrosion and wear in the steam generator (SG) can have a considerable influence on the output and availability of the whole plant. At a very early stage, Siemens embarked on careful analysis of the damage mechanisms registered worldwide. The results of this evaluation have continuously been incorporated into the design and operation of steam generators and of the associated steam/water cycles. The KWU Group of Siemens now has 62 SG's in operation. The good performance of these SG's relies on harmonizing the design of the SG, the structural materials used and the operating water chemistry. The following describes the forms in which damage occurs and the Siemens concept for combatting the problem. (author)