The test operation of the Tokyo Tech rotary-type solar reactor (2nd model) is scheduled to be carried out using the solar concentrating system of CSIRO (New castle, Australia) as an international collaboration research between Japan (Tokyo Tech) and Australia (CSIRO) in APP (Asia-Pacific Partnership on Clean Development and Climate) project. The rotary-type solar reactor is positioned at an elevation of about 17 m. The input of solar power for the test operation is planned to be 50 kW from the solar concentrating system with about 10 heliostats. The estimation of evolved H2 gas was calculated from the amount of evolved O2 gas and the energy conversion efficiency is evaluated from the estimated amount of evolved H2 gas and the input of solar energy. The two-step water splitting process with the reactive ceramics of ceria-based solid solution (0.8CeO2 −0.2ZrO2 prepared by the polymerized complex method) was investigated using the solar simulator of concentrated Xe lamp beams for the test operation of the rotary-type solar reactor at CSIRO solar concentrating system. The amounts of O2 and H2 gases evolved in the two-step water splitting reaction with CeO2 -ZrO2 solid solution were determined for the H2 -generation reaction temperatures of 773, 1273 and 1473 K. The amounts of evolved H2 gas decreased with an increase of the reaction temperature, however, the lowering of H2 gas evolution at 1473 K was 20% in comparison with that at 773 K. The heating time of the reactive ceramics up to the O2 -releasing reaction temperature is evaluated to 3 s, when the difference between the O2 -releasing reaction temperature (1773 K) and the H2 -generation reaction temperature (1473 K) is 300 K.Copyright © 2009 by ASME