被覆管多軸応力負荷試験装置の開発と特性試験結果

Development and test results of multi-axial stress testing machine for cladding

福田 拓司; 杉山 智之 ; 三原 武  ; 天谷 政樹  ; 永瀬 文久 

Fukuda, Takuji; Sugiyama, Tomoyuki; Mihara, Takeshi; Amaya, Masaki; Nagase, Fumihisa

高燃焼燃料のRIA条件下では被覆管と燃料ペレットのボンディングが生じており、多軸応力状態となる。このような応力状態を炉外で模擬するために被覆管試験片に対して、内圧と軸力の荷重負荷を独立して制御できる試験機を開発した。本報告では本試験装置を用いて実施した常温の特性試験結果について報告する。

The stress condition of the cladding tube of high burnup fuel is complicated under RIA (Reactivity Initiated Accident) condition because fuel pellet and cladding bond significantly in high burnup fuel. The stress condition becomes biaxial under such condition due to the isotropy of pellet thermal expansion. We have developed a biaxial stress testing machine which can control the axial and circumferential stresses independently and evaluate the mechanical and fracture behaviors of cladding tube under biaxial stress condition. This report describes the outline of the experiment using this equipment and the test results obtained under several biaxial stress conditions at room temperature.