Ongoing SCC studies on Alloy 690 and its weld metals show that vulnerabilities exist that can increase the growth rates by 1000X. The primary vulnerabilities evaluated relate to microstructural homogeneity and cold work. With sufficiently high cold work roughly above 20% high crack growth rates are observed. This appears applicable to most even very high quality heats and forms of Alloy 690. This paper summarizes on-going work on the effect of cold work and the orientation of the crack plane in relation to cold work. Various heats of Alloy 690 have been studied ranging from plates to control rod drive mechanism (CRDM) housings. This paper also summarizes extensive testing on Alloy 152 and 52 weld metals which consistently show very low growth rates apart from one case where 20% additional strain was applied to the weld metal. Other studies in progress have characterized various welds and heat affected zones and are beginning to evaluate conditions of greater concern i.e. related to weld repairs and welds with re-fuse layers both of which increase the residual strain levels.