The structural materials currently used in many BWR structural applications such as stainless steels and nickel based alloys exhibit significant susceptibility to stress corrosion cracking with Cr levels in the 15-18 wt% range although these types of alloys with Cr levels in the 27-30 wt% range have been shown to result icn a significant reduction in SCC susceptibility. The effect of Cr level in stainless steel and nickel based alloys on SCC behavior was investigated under various water purity conditions electrochemical potentials and stress intensity factor levels in 288C water. The purpose of this research was to identify stainless steel and nickel based alloys with Cr levels from 20 to 30 wt% and determine their resistance to cracking under various water chemistry and loading conditions