Experimental study and kinetic analysis on sodium oxide-silica reaction

Kikuchi, Shin  ; Koga, Nobuyoshi*; Seino, Hiroshi ; Ohno, Shuji  

In a sodium-cooled fast reactor (SFR), if considering hypothetical severe accidental condition such as the steel liner failure of structural concrete caused by intensive leakage of liquid sodium (Na) coolant, the liquid sodium-concrete reaction (SCR) may take place. The major consequences of SCR are hydrogen release, energy release and concrete ablation. Thus, it is important to understand the phenomenology of SCR. As a part of a series of studies on SCR, this study focused on the reaction between sodium oxide (NaO) and silica (SiO). Through thermoanalytical and X-ray diffraction measurements, it was revealed that NaO-SiO reaction to form sodium orthosilicate (NaSiO) occurs at significantly lower temperature in comparison with Na-SiO reaction.