抄録
Design extension conditions (DEC) induce some different failure modes from design conditions. Furthermore, the best estimation for these failure modes is required for preparing countermeasures and management. Therefore, this study focused on identification failure modes under DEC. To realize best estimation, it is prerequisite to clarify failure modes with ultimate structural strength under extreme loadings such as very high temperature and pressure. In this paper, relations between failure modes and extreme loadings were investigated by the numerical simulation using the cylindrical model of lower formed head of reactor pressure vessel.
