Abstract
The defect behavior is one of the principal concerns to be dealt with for the structural integrity since defects may lead to the failure of SFR(Sodium-cooled Fast Reactor) structure under high temperature loading conditions. A thin-walled and large diametric piping is adopted for the IHTS (Intermediate Heat Transport System) piping system of SFR to enhance the system economy and to reduce the thermal stress. The structural material for the piping is Type 316 austenitic stainless steel. In this study, the defect growth evaluation of IHTS piping was performed for the semi-elliptical surface defect subjected to the combined mechanical loading and the thermal loading of a high temperature above 500・・ including a cyclic loading condition corresponding to the reactor refueling cycle. The creep-fatigue defect behavior evaluations are carried out following the French Assessment Procedure A16, the UK Assessment Procedure R5/R6 and the Japanese procedure. The results are compared each other and the strong and weak points are discussed. Also the degree of conservatism of each procedure is reviewed.
