Lawrence Berkeley National Laboratory

Complexation of actinides with a wide variety of ligands has been studied for a few decades, but the majority of the data are for room temperature. Since the temperature of the nuclear wastes in storage tanks is significantly above 25 degrees C, lack of thermodynamic data at elevated temperatures makes it difficult to understand and predict the chemical behavior of actinides in waste processing. In this work, complexation of actinides with a series of carboxylic acids was studied by variable temperature potentiometry and calorimetry in a temperature range of 25 degrees C to 70 degrees C. These data, in conjunction with the characterization of species by spectrometry, help to develop strategies for nuclear waste treatments.