Influence of applied load on oxidation in the vicinity of crack tips of stainless steel under high temperature water

Kasahara, Shigeki; Chimi, Yasuhiro; Hata, Kuniki; Hanawa, Satoshi

Zairyo To Kankyo, 68(9), p.240 - 247, 2019/09

https://doi.org/10.3323/jcorr.68.240

In order to study environment assisted cracking mechanism of stainless steel under BWR primary coolant condition, effects of applied load on oxidation in the vicinity of crack tips of CT specimens were evaluated. Loaded CT specimens were immersed in an aqueous condition at 290C as a simulated BWR coolant condition, and microstructural observation on oxide near the tips of pre-cracks was carried out. Oxide inner layers, which consisted of fine grain magnetite containing Fe and Cr were formed, and oxide outer layers consisting of large grains of FeO were observed to cover the inner layers. FEM analysis of stress and strain in the loaded CT specimen suggests that both of dislocations due to localized plastic deformation and elastic strain could play important roles to accelerate inner oxide formation in the vicinity of the crack tip of the specimens.

Assessment of core status of TEPCO's Fukushima Daiichi Nuclear Power Plants, 109; Difference in core energy in core material relocation in Units 2 and 3 of FDNPS and its effects

Sato, Ikken; Yamashita, Takuya; Yoshikawa, Shinji; Li, X.; Pellegrini, M.*; Yamaji, Akifumi*; Kojima, Yoshihiro*

no journal, , 

Difference in core energy between Unit 2 and Unit 3 is evaluated and its effects on coolability of debris relocated to lower plenum and debris-relocation behavior to pedestal are discussed.

BWR lower plenum damage by reaction between metallic debris and structural materials

Sato, Takumi; Shimomura, Kenta; Nagae, Yuji

no journal, ,