The radiation-thermal-catalytic processes of water decomposition in the n-ZrO2-n-Al2O3+H2O system are investigated. The kinetics of molecular hydrogen accumulation was studied during radiolytic processes of water decomposition in the systems under study. The values of the accumulation rates and radiation-chemical yields of hydrogen during the radiolysis of water in the n-ZrO2-n-Al2O3+H2O system at various temperatures have been determined. Besides this, it was shown that the results obtained serve as a base for checking the scenarios of normal and emergency conditions of nuclear reactors refrigerated by water.