Thermal hazard analysis of hydrazine and nitric acid mixtures

In order to obtain a better understanding of the thermal hazard of hydrazine and nitric acid mixtures which are used in PUREX (Plutonium and Uranium Recovery by Extraction) process during recycling of spent fuel in nuclear plant, DSC and small scale reaction calorimetry super-CRC were carried out for the mixtures in various conditions. From the DSC analysis the apparent activation energy of hydrazine monohydrate in SUS 303 crucible was determined to be 96 kJ mol-1. The mixing hazard of hydrazine monohydrate with nitric acid was measured with super-CRC and the results suggested that the concentration and the mass of nitric acid had a strong influence on the mixing heat of reaction of the system.