A Reliability Based Contour Fatigue Design Approach for Nuclear Piping

Abstract

One solution to improve over margin design for piping is to apply reliability based approach. By applying limit state function method in design stage, safety margin can be expressed explicitly as reliability index. From practical point of view, however, it is rather complicated for designer to perform reliability approach every time at design stage. Thus, this paper proposes a reliability based contour design curves which are derived from the uncertainty both for Markl’s best fit curve and for loads. Using this method, reliability based fatigue design can be done easily for the given reliability target. This paper shows the derivation of reliability based contour design curve together with some calculation results and finally proposes the simplified procedure.