Technical Manager, Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama,
Engineer, Kobe Shipyard and Machinery Works, Mitsubishi Heavy Industries Co., Ltd., Kobe,
Professor, Doctor of Engineering, University of Tokyo, Tokyo,
Pages: 16 Published: Jan 1997
The recently acquired fatigue test data have indicated that the low cycle fatigue lives attained in light water reactor environments can be markedly shorter than those determined in the ambient atmospheric air. Of the various factors that are known to exert influence on the fatigue life, the present authors have noted strain rate, temperature, and dissolved oxygen (DO) content, and proposed a method of evaluating the environmental fatigue lives for the Class 1 vessels when they vary with time. In this paper, this method is examined against, and revised in view of, the fatigue data acquired since then, and subsequently simplified so as to become adaptable to the Class 1 piping besides the Class 1 vessels. Then, these two versions of this evaluation method are combined into a methodological system by their respective nature, and, in doing so, have proved their worth by applying themselves to several different sorts of component. The results show that the effects of the light water reactor environments on the fatigue life is a factor of 2 or so in terms of the increase of the usage factor (i.e., the environmental effect correction factor Fen = ca. 2).
ASME Code, fatigue life, fatigue evaluation, light water reactor component, environmental effect, strain rate
Paper ID: STP19967S