Environmentally Assisted Fatigue Evaluation Model of Alloy 690 Steam Generator Tube in High-Temperature Water

Based on corrosion fatigue tests using a boat-shaped specimen in borated and lithiated high-temperature water, the corrosion fatigue behavior of Alloy 690 tubes was investigated. An Institute of Metal Research fatigue model for the nickel-based alloys is proposed, which incorporates fatigue life data of Alloy 690 tubes, as well as round-bar specimen data from the open literature. The proposed environmental fatigue life correction factor Fen addresses the effects of temperature, strain rate, and dissolved oxygen concentration. An evaluation methodology for environmental fatigue damage of structural materials in nuclear power plants is proposed.