Small specimen test technology of fracture toughness in structural material F82H steel for fusion nuclear reactors

核融合炉構造材F82H鋼の小型破壊靭性試験片等を用いた強度評価技術

若井 栄一  ; 大塚 英男; 松川 真吾*; 安堂 正己; 實川 資朗

Wakai, Eiichi; Otsuka, Hideo; Matsukawa, Shingo*; Ando, Masami; Jitsukawa, Shiro

放射性廃棄物量の低減と国際核融合材料照射施設(IFMIF)用コンポーネントの材料評価などのために、微小破壊靭性試験片を用いた強度特性評価及び、このための破壊靭性試験装置の開発を実施した。本報告書では、核融合炉用構造材料として開発したF82H鋼(Fe-8Cr-2W-0.1C系マルテンサイト鋼)を用いて、微小破壊靭性試験片作製法やこの微小試験片の靭性評価に及ぼす試験片サイズの効果、さらに、動的及び静的な試験方法による延性脆性遷移温度に関する研究成果と開発した試験装置の性能などをまとめたものである。また、これら微小破壊靭性試験片を用いて、2005年に約2dpaまでJMTR炉で中性子照射した試料リストを記載した。

Small specimen test technology (SSTT) has been developed to investigate mechanical properties of nuclear materials. SSTT has been driven by limited availability of effective irradiation volumes in test reactors and accelerator-based neutron and charged particle sources, and it is very useful for the reduction of waste materials produced in nuclear engineering. In this study new bend test machines have been developed to obtain fracture behaviors of F82H steel for very small bend specimens of pre-cracked -CVN (Charpy V-notch) with 20 mm-length and DFMB (deformation and fracture mini bend specimen) with 9 mm-length and disk compact tension of 0.18DCT type, and fracture behaviors were examined to evaluate DBTT (ductile-brittle transition temperature) at temperatures from -180 to 250C. The effect of specimen size on DBTT of F82H steel was also examined by using Charpy type specimens such as -CVN, CVN and -CVN. In this paper, it also provides the information of the specimens irradiated at 250C and 350C to about 2 dpa in the capsules of 04M-67A and 04M-68A of JMTR experiments.