Effects of nature of grain boundary on void distribution during irradiation in austenitic stainless steels

Sekio, Yoshihiro  ; Yamashita, Shinichiro   ; Yoshitake, Tsunemitsu ; Nishinoiri, Kenji; Takahashi, Heishichiro

The process of the irradiation-induced defects accumulation during irradiation has not been clarified yet, namely what microstructural factors affect defect accumulation process. For this reason, we investigated the void distribution near grain boundaries by focusing on grain boundaries as a microstructural factor in Fe-15Cr-15Ni model alloy and PNC316 stainless steel used for the nuclear fast reactor. It was clarified that the void denuded zone were formed near only a random grain boundary under neutron irradiation in Fe-15Cr-15N alloy and PNC316 stainless steel as being observed in the electron-irradiated austenitic stainless steels. We discussed the difference of the void denuded zone distribution in both steels under low and high fluencie. These results suggest that the grain boundary characteristics and its effect on void denuded zone formation will play a role for the void swelling under neutron irradiation in austenitic stainless steels.