Nonsensitized Type-304 stainless-steel fuel cladding cracked intergranularly when exposed to high-temperature, high-purity, water reactor environments. Similar failures were produced out of reactor in stressed tubular-capsule specimens exposed to dilute solutions of iron chloride, copper chloride, sodium hydroxide, and chromic acid at 650° F (343°C). An iron chloride test was developed that closely simulates the intergranular attack on stressed nonsensitized Type-304 stainless-steel fuel cladding. Stressed, cold-worked, nonsensitized Type-304 stainless-steel tubing cracked in less than 24 h at 650° F when exposed to ferric-ferrous chloride solutions containing only 40 Cl parts/106 and 4 soluble-iron parts/106. Exposure at 650° F caused intergranular cracking only, while exposure at 550° F (288° C) caused mixed transgranular and intergranular cracking. The accelerated autoclave test can be used for screening of prospective cladding materials and alloy modifications and developing a better understanding of the mechanism of attack.