Intensely irradiated steel components; Plastic and fracture properties, and a new concept of structural design criteria for assuring the structural integrity

高照射損傷を受ける鋼製機器; 塑性及び破壊特性、並びに、構造健全性を確保するための構造設計基準の新概念

鈴木 一彦; 實川 資朗; 大久保 成彰   ; 高田 文樹

Suzuki, Kazuhiko; Jitsukawa, Shiro; Okubo, Nariaki; Takada, Fumiki

Review of mechanical properties of structural materials under intense neutron irradiation reveals several critical issues to be dealt with in developing a concept assuring the structural integrity of a component under such irradiation. Among these issues are possible reduction in ductility, significant change in mechanical properties, remarkable cyclic softening and other unique cyclic properties observed during a high-cycle fatigue testing, and the redundancy of the plastic collapse concept to bending. Therefore, a new concept for assuring structural integrity is required for application not only to components with high ductility but also components with reduced ductility. First, fracture ductility and the relation of true stress and true strain were formulated. Then, potential failure modes were identified, and a new and systematic concept is here proposed for preventing these modes of failure.