Looking for a future use of hydrogen as the energy vector able to replace fossil use, one of the main problem still to be solved is its storage. The hydrolysis of chemical hydrides represent a safe and convenient way to store and produce hydrogen “on demand” at moderate temperature and atmospheric pressure. Among chemical hydrides, one of the most promising is sodium borohydride (NaBH4). Its use as hydrogen storage medium has been extensively studied dissolved in a NaOH solution (up to 30% in weight). To maximize hydrogen gravimetric capacity we propose to use solid catalyzed NaBH4. Since the water requested for the reaction strongly depends on the hydratation state of the sodium borate (that is the reaction product), several experiments have been done to check the minimal amount of water that need for the reaction. Nickel catalyzed NaBH4 powder was used as the starting material and it was hydrolyzed in a reactor using water or steam. Several test have been done under various hydrolysis conditions. The present paper shows the results obtained during the hydrolysis reporting the evolution of the hydrogen as a function of catalyst, water inlet flow, temperature and reactor geometry.