Creep–fatigue evaluation of stainless steel welded joints in FBR class 1 components Original Research Article

This paper describes a creep–fatigue evaluation method of 316FR welded joints proposed for the design of large-scale Japanese fast breeder reactors. The mechanism that cause the life reduction of welded joints were assumed to be stress/strain concentration due to the discontinuity of inelastic deformation properties within welded joints and the weaker strength of weld metal. This was verified by FE-analyses that simulated uniaxial fatigue/creep–fatigue tests of 316FR welded joints. A creep–fatigue evaluation method for 316FR welded joints was consequently proposed. The method was based on the elastic follow-up concept and gave strain concentration factors as a function of strain range, which methodology was an extension of the one previously proposed for the SUS304 welded joint. The method predicted the uniaxial creep–fatigue life of 316FR welded joints with reasonable margins of safety.