3. Stress corrosion degradation of stainless steels in polluted environments in PWR reactors

Austenitic stainless steels are highly resistant to stress corrosion in the primary environment of nominal PWRs, where they crack only under very specific conditions, either when they are highly work-hardened and subjected to very severe mechanical stress, or when they have undergone significant irradiation [BN 3 755] .

On the other hand, the presence of oxygen and/or impurities, of which chlorides are the most dangerous, can lead to cracking of austenitic stainless steels: experience in boiling water reactors (BWR) has shown that the presence of dissolved oxygen is sufficient to cause stress cracking of sensitized or highly work-hardened stainless steels. The additional presence of chlorides (and possibly sulfates) can lead to transgranular cracking, even in the absence of sensitization....