[en] U-bend leakage in Row 1 steam generator tubes has been reported at some operating plants. The leakage in these U-bends has been attributed to stress corrosion cracking that initiated at the ID surface of the tubes. The objective of Project S191-3 is to demonstrate the feasibility of heating the U-bends from the bore of the tube to a temperature that will reduce the residual stresses at the U-bend and thereby provide added resistance to stress corrosion. A number of U-bends fabricated from 3/4-inch and 7/8-inch O.D. mill annealed Inconel Alloy 600 tubing were heated to 788₀C (1450₀F) for 15 minutes using specially designed electrical resistance heaters. The results of these tests showed that the resistance heaters were capable of heating the U-bends to the desired temperatures and thus cause a significant reduction in the residual stresses. However, a desired improvement in microstructure was not detected. No significant distortion in the U-bends was detected, but the tube support plate was heated sufficiently to possibly cause unacceptable local thermally induced stresses