Study on preventive maintenance of core structural components by evaluating the influence of residual stress on irradiation assisted stress corrosion cracking behavior

Miwa, Yukio; Kondo, Keietsu  ; Okubo, Nariaki   ; Kaji, Yoshiyuki  

This study proposed an evaluation method of damage occurrence of core structural materials by simulation model. Irradiation assisted stress corrosion cracking (IASCC) is one of the damage modes among aged core components. IASCC was thought to be caused by material degradation such as losses of workability due to radiation hardening and corrosion resistance due to radiation-induced segregation and residual stress due to welding, then the influence of residual stress on both radiation hardening and radiation induced segregation was examined by ion-irradiation experiments. Not only the residual stress change due to radiation creep was affected by residual stress and dose, but also the material degradation was affected. This was modeled and the damage occurrence by IASCC in a shroud type component during reactor operating life was estimated by means of FEM calculation based on the models of the material degradation and residual stress.