Abstract: Considering the abnormal thickness reduction of the titanium heat transfer tubes in some SRI heat exchangers of a nuclear power plant, the chemical composition of raw material, performance, working medium, flow induced vibration and fretting damage are studied It is found that the primary causes for the failure are the flow induced vibration between tubes and baffle rod, and the fretting damage. A series of specific countermeasures is provided. The achievements obtained can provide as an instructive reference to ensure the effective protection and safe operation of heat exchangers running under the circumstance of seawater in nuclear power plants.