The occurrences of intergranular stress-corrosion cracking in nuclear power plant components made of austenitic alloys are discussed. Cracks of this type have occurred in sensitized Types 304 and 316 austenitic stainless steels in a variety of components at various stages of fabrication. Historically, cracking in early reactors occurred in heavily sensitized material or were related to the presence of chlorides or caustic ions. More recently, a rash of cracks were found in boiling water reactor piping adjacent to welds. This problem is evaluated.

Wastage and intergranular cracking of Inconel 600 alloy tubing of steam generators has occurred in the secondary side in plants that have used either sodium phosphate or all volatile water treatment. Design and environmental factors have had a pronounced influence on the tube degradation. The significance of these conditions is discussed, as is action taken by the Nuclear Regulatory Commission relating to this problem.