Tensile properties of modified 316 stainless steel (PNC316) after neutron irradiation over 100 dpa

100dpaを超えて中性子照射したPNC316の引張特性について

矢野 康英  ; 上羽 智之 ; 丹野 敬嗣  ; 吉武 庸光 ; 大塚 智史   ; 皆藤 威二 

Yano, Yasuhide; Uwaba, Tomoyuki; Tanno, Takashi; Yoshitake, Tsunemitsu; Otsuka, Satoshi; Kaito, Takeji

高速実験炉「常陽」で中性子照射したPNC316の引張特性に及ぼす中性子の影響を評価した。PNC316被覆管とラッパ管は、照射温度400ら735Cで照射量21から125dpaで照射された。照射後の引張試験は室温と照射温度で実施された。照射材の著しい硬化と軟化は確認されたが、照射後の引張延性は工学的なレベルを維持できていた。また、400から500Cの範囲で110dpa照射されたPNC316ラッパ管の最大スエリング量は2.5%であり、10%以上のスエリングが生じたPNC316や15Cr-20Ni鋼のような日本の20%冷間加工材は、塑性不安定は小さかったけれども、十分な延性と加工硬化性能を維持していることが分かった。

The effects of fast neutron irradiation on tensile properties of modified 316 stainless steel (PNC316) claddings and wrappers for fast reactors were investigated. PNC316 claddings and wrappers were irradiated in the experimental fast reactor Joyo at irradiation temperatures between 400 and 735 C to fast neutron doses ranging from 21 to 125 dpa. The post-irradiation tensile tests were carried out at room and irradiation temperatures. Elongations of PNC316 measured by the tensile tests were maintained at an engineering level, although the material incurred significant irradiation hardening and softening. The maximum swelling of PNC316 wrappers was about 2.5 vol.% at irradiation temperature between 400 and 500C up to 110 dpa. Japanese 20% cold-worked austenitic steels, PNC316 and 15Cr-20Ni, had sufficient ductility and work-hardenability even after above 10 vol.% swelling, while they had very weak plastic instabilities.