In this paper, new experimental data is presented for the hydrolysis of steam with CuCl2 particles, in a high-temperature fluidized-bed reactor, which is a critical component of the Cu-Cl hydrogen production cycle. Results are obtained from large engineering-scale equipment built to perform the hydrolysis reaction using steam and CuCl2. Experimental facilities are utilized for a boiler and superheater to supply steam for the endothermic reaction to proceed. This paper provides new insight into the hydrolysis operation by examining various issues involving the reaction rate and integrating the hydrolysis reactor into the Cu-Cl cycle. The results indicate a 40% reduction in the experimental reaction rate, during the initial 30 min of the reactor operation, as physical rate-controlling resistances develop in the process. This paper analyzes the process, in terms of chemical reaction rates, and limiting the physical resistances to efficient reaction rates within the reactor, as needed for the Cu-Cl cycle to become more economically competitive against other methods of hydrogen production. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.