Secondary and auxiliary circuit materials for pressurized water reactors
Corrosion of Nickel Alloys and Stainless Steels in Pressurized Water Reactors

The vast majority of PWR secondary circuit components are made of carbon or low-alloy steel, whose protection against corrosion and, in particular, erosion corrosion, dictates the principles of water treatment.

The other materials present in quantity in the secondary circuit are as follows:

• Nickel alloys for steam generator (SG) tubes: alloy 600, then alloy 690 since the late 1980s, or alloy 800 (iron-based, medium nickel content) in Germany and Canada;

• austenitic stainless steels type 18-10 (type 304) or 17-12-Mo (type 316) – which are used in the tubes of feedwater heaters, condensate coolers, dryer-superheater units and condensers. In France, the main austenitic stainless steel grades (304 and 316) have low carbon contents, below 0.03% (types 304L and 316L), guaranteeing good resistance...