Development of failure evaluation method for BWR lower head in severe accident, 1; High temperature creep test and creep damage model

シビアアクシデント時におけるBWR下部ヘッドの破損評価手法の開発,1;高温クリープ試験とクリープ損傷モデル

山口 義仁 ; 勝山 仁哉  ; 加治 芳行  ; 吉田 啓之  ; Li, Y. 

Yamaguchi, Yoshihito; Katsuyama, Jinya; Kaji, Yoshiyuki; Yoshida, Hiroyuki; Li, Y.

After the Fukushima Daiichi Nuclear Power Plant accident due to the pacific coast of Tohoku earthquake and Tsunami, we have been developing an analysis method considering creep damage mechanisms based on three-dimensional analysis for the early completion of the decommissioning of nuclear power plants. We have also been obtaining material properties which are not provided in existing database or literature for the analysis. In this study, we measure the tensile and creep properties for low alloy steel, Ni-based alloy and stainless steel at high temperature near the melting points. Using the experimental data, some parameters for the creep constitutive law and creep failure evaluation method are determined. In addition, through the comparison in creep rupture time between finite element analysis and experiment, the validity of failure evaluation method is confirmed.