Hydroxyurea and its derivatives are important nonsalt forming reductants in partitioning of uranium and plutonium in the nuclear
fuel reprocessing operations. There is no experimental data available in open literature describing pressurization due to
the thermal decomposition of aqueous and nitric solutions of hydroxyurea at elevated temperatures. Authors studied thermal
decomposition of hydroxyurea-nitric acid system and resultant pressurization at various concentrations of nitric acid in an
adiabatic calorimeter in closed-vent conditions. During these experiments, pressurization was observed. In this paper, results
of these experiments have been discussed.