EPMA analysis of multi-component interaction products between boron carbide and stainless steel under a postulated core disruptive accident in SFR

Nakamura, Kinya*; Ota, Hirokazu*; Takai, Toshihide  ; Yamano, Hidemasa   

To investigate in-depth redistribution behavior of the constituent elements of BC and SS, electron probe microanalysis was applied to the multi-component interaction products held at 1500C for 8 min approximately in argon gas atmosphere in this study. The results indicated that relatively low-density boron was preferentially diffused the upper surface of the molten SS horizontally to form acicular and high melting point compound (Cr,Fe)B along with the eutectic microstructure composed of (Fe,Cr,Ni) solid solution and (Cr,Fe)B. According to the macroscopic quantitative analysis, average chemical concentration of boron is almost uniform in the horizontal direction regardless of the distance from the BC pellet but decreased toward the bottom in the molten SS monotonously in the vertical direction.