Corrosion in molten sodium systems results in liberation of hydrogen. Sodium hydride thus must be removed by the purification system. In order to study the dehydrogenation behavior, a dynamic crystallization analysis was carried out on a cold trap packed with wire mesh packings. This analysis accounted for mixing in the crystallizer, hydride buildup on the packing, and precipitation of hydride in different portion of packing section. The results showed that this model would be useful for assisting cold trap designer to achieve the optimum design for specific application.