Development of the guideline on inelastic analysis for design

Tanaka, Yoshihiko; Shibamoto, Hiroshi; Inoue, Kazuhiko; kasahara, Naoto; Ando, Masanori; Ito, Kei

The guideline on inelastic analysis for design, one of the key items of Fast Reactor Design Standard(FDS), is being developed.The basic policies of this guideline are as follows:(a) to emphasis conservative analysis output rather than nominal value representing actual behavior, (b) to clarify the applicable area for assurance of conservative results. With such concepts, it would be possible that the guideline provides useful explanations on the manner of analysis and estimation in the form of concrete examples of design as well as general rules (somehow vague). As the first step of the guideline development, the following five issues to be solved were extracted:1) applicable area, 2) selection of constitutive equation, 3) modeling method of the load history, 4) ratchet strain and creep fatigue damage evaluation methods by inelastic analysis and 5) example design problems to check users' analysis quality and to complement the general rules. In parallel, inelastic analyses with the promising constitutive equations were applied by way of trial to obtain rough presumption on their effects on structural design of the components. As a result,all inelastic analyses provided smaller cumulative strains and equivalent strain ranges than the existing design method based on elastic analysis,suggesting advantage of introducing them into actual design.