Strain-induced corrosion cracking of low-alloy steels in LWR systems - case histories and identification of conditions leading to susceptibility

The term ''strain-induced corrosion cracking'' (SICC) is introduced to describe crack formation involving dynamic straining, but in the absence of obvious, cyclic loading. It origins in slow-strain-rate testing and in corrosion failures in boiler systems are described and the links with ''classical'' stress corrosion cracking and low-cycle corrosion fatigue are identified. Four areas, in which SICC of low-alloy steels in LWR systems has occurred, are described in detail and the typical features are used, together with literature data from laboratory testing, to identify conditions leading to susceptibility. Indications are given of remedial measures and of ares in which further work is necessary. (orig.)