抄録
A series of thermal transient fatigue tests on five SUS304 stainless steel straight pipe models with circumferential weld joints and a nozzle model were performed to study the general behavior of crack initiation and growth including crack locations, directions and densities under respective loading conditions. The crack initiation sequence at different parts of models corresponded well with the result of analytical prediction using the finite element method. The potential margin on the allowable number of thermal transient cycles according to the ASME CODE CASE N-47 and the Elevated Temperature Structural Design Guide developed by the Power Reactor and Nuclear Fuel Development Corporation was evaluated, and the result showed a considerable safety margin compared with the data on initiation of cracks of 1 mm in depth at all parts of pipe models including circumferential weldings, notches, and other structural discontinuities.
