In order to investigate the later phase of a sodium-water reaction (SWR) event in KALIMER (Korea Advanced LIquid MEtal Reactor), the code SELPSTA (Sodium-water reaction Event Later Phase System Transient Analyzer) has been developed and an experimental study has been carried out for verification of the simple analysis model applied to the code. The 24 data set obtained in the experiment have been pre-analyzed. Comparison of SELPSTA results with experimental data shows fairly good agreement in the transient.