Assumption and comparison of fuel debris properties between TMI-2 and 1F for future defueling work

Kitagaki, Toru  ; Ikeuchi, Hirotomo  ; Yano, Kimihiko ; Hoshino, Takanori ; Kaji, Naoya; Washiya, Tadahiro 

Objective of this research is to estimate deferences of debris between TMI-2 and 1F and to clarify improvement points of the defueling tools used at TMI-2. In this study, mechanical properties of (U,Zr)O with Zr content and O/M ratio between TMI-2 and 1F were compared. Zr content of 1F debris will be higher than TMI-2. Because vickers hardness of (U,Zr)O increase with Zr content, so vickers hardness of 1F will also be slightly higher than that of TMI-2. Moreover, it was shown that vickers hardness and fracture toughness increase with O/M ratio. In the case of high oxide potential in 1F, vickers hardness and fracture toughness of fuel debris increase. In this assumption, accelerate of wear and increasing of friction of core boring tool are indicated, so improvement of wear resistance and torque will be needed.