Melting behavior of sodium peroxide produced by sodium fire

Kikuchi, Shin  ; Koga, Nobuyoshi*

Sodium peroxide is one of the reaction products of sodium fire, which occurs by the reaction between liquid sodium and oxygen. Melting and evaporation behavior of these sodium oxides are key elements for evaluating plant safety and structural integrity of sodium-cooled fast reactor in relation to the influence on the ambient temperature in case of sodium fire. However, the phase change behavior of sodium oxides is not well revealed because of the experimental difficulties due to high temperature environment and significant chemical reactivity of sodium oxides. In this study, the melting behavior of sodium peroxide was investigated using differential scanning calorimetry (DSC). After careful temperature and energy calibrations of the DSC instrument, enthalpies of sodium peroxide transition and melting were obtained for validating the sodium fire analysis code.