Abstract
The Commissariat a L'Energie Atomique (CEA, French Atomic Energy Agency) and AREVA NC have developed new acidic surfactant liquid solutions to remove organic matter located at the surfaces of equipment used in reprocessing facilities. The aim of developing acidic formulations is to avoid sodium hydroxide to prevent uranium and plutonium oxides to precipitate and to ease the glass conditioning of the final liquid wastes. The organic matter providing the contamination is a solvent widely used in nuclear industry as a complexing agent of uranium and plutonium, the tributylphosphate (TBP). The purpose of this work is to understand and adapt the mechanisms involved in the TBP detachment and solubilization in acidic surfactant solution. In order to reach an optimal effectiveness, two well-known mechanisms should be combined: roll-up and emulsification. These mechanisms are characterized with a CCD camera allowing us to measure contact angles between a solid substrate and a liquid drop. For this work, we measured contact angles of a TBP drop deposited on a stainless steel plate, immersed in an acidic surfactant solution bath. In addition, we quantified the amount of TBP solubilized in the micelles by turbidity measurements. As a result, we formulated new acidic surfactant solutions with improvement factors in various fields (total organic matter amount, oil detachment and solubilization efficiency, emulsion stability…)
