The Effects of irradiation defect distribution and the steel compositions on void denuded zone formations during neutron irradiation and electron irradiation

中性子照射及び電子線照射下におけるボイド欠乏帯形成に及ぼす照射欠陥分布と材料組成の影響

関尾 佳弘  ; 山下 真一郎   ; 坂口 紀史*; 高橋 平七郎*

Sekio, Yoshihiro; Yamashita, Shinichiro; Sakaguchi, Norihito*; Takahashi, Heishichiro*

結晶粒界近傍に形成される照射誘起のボイド欠乏帯に及ぼす照射欠陥分布と合金元素の効果を調べる目的で、Fe-15Cr-15Ni(モデル合金)とPNC316について中性子照射後並びに電子線照射後の微細組織観察を実施した。その結果、ボイド欠乏帯の幅は、照射欠陥分布には影響されなかったものの、合金元素には大きく影響を受け、照射欠陥の易動度の減少によりボイド欠乏帯が小さくなることがわかった。PNC316は耐スエリング特性向上のために添加元素を積極的に導入している鋼種であることから、これらの結果は、ボイド欠乏帯の減少と耐ボイドスエリング特性向上が密接に関係していることを示唆している。

The irradiation-induced void denuded zone (VDZ) formation behaviors near grain boundaries were studied in order to clarify the effects of irradiation defect distribution and chemical compositions of steels which were developed to retard their swelling because of the decrease in mobility of point defects during irradiation. The test materials were Fe-15Cr-15Ni model alloy and PNC316 stainless steel which was developed in order to improve the void swelling resistance. These steels were neutron-irradiated in the experimental fast reactor JOYO and electron-irradiated separately using the 1 MeV high voltage electron microscopy (HVEM). The VDZ widths of each steel were evaluated by the TEM microstructural observations after irradiation. From the results in this research, it is considered that VDZ formation would be affected by chemical compositions and that the decrease of VDZ width would be related to increase of the void swelling resistance.