Experimental study and kinetic analysis of sodium-water chemical reaction mechanism in steam generator of sodium-cooled fast reactor

For the purpose of elucidating the mechanism of the sodium-water surface reaction in a steam generator of sodium-cooled fast reactors, kinetic study of the sodium (Na)-sodium hydroxide (NaOH) reaction has been carried out by using Differential Thermal Analysis (DTA) technique. Based on the measured reaction temperature, the first-order rate constant of sodium monoxide (Na2O) generation was obtained by the application of the laws of chemical kinetics. From the estimated rate constant, it was reconfirmed that Na2O generation should be considered during the sodium-water reaction in spite of variation of volume fraction (Na:NaOH). Na, NaOH and Na2O as major chemical species were identified from the X-ray diffraction (XRD) analysis of the residues after the DTA experiment. It was inferred that Na2O could be generated as a reaction product. (author)