ELIPSE: An innovative technology for the treatment of radioactive organic liquids

The CEA is studying the development of processes with a sufficiently large operating range in order to propose a general treatment system and make it possible to absorb a significant quantity of radioactive liquid stocks awaiting treatment around the world. A solution may be the use of submerged plasma into which the organic liquids would be injected. Current research has demonstrated that such a technique may enable the instantaneous and complete destruction of liquids with a wide variety of constituents, such as chlorine, fluorine, or phosphorus. The ELIPSE process was designed based on the results of this research. In this process, an arc plasma torch is submerged in the core of an aqueous solution. The submersion solution offers many advantages: quenching and cleaning of combustion gases; filtering of the particles they contain; and cooling maintained for the entire process, which guarantees excellent corrosion control. An advantage of this type of design is that the gas treatment system can be reduced to a demister-condenser followed by a simple safety filter, thereby offering the additional advantage of an extremely compact treatment system. This design also allows the ELIPSE process to become by this way an embeddable process if required. The present paper will first describe the state of the art concerning this concept and secondly research currently conducted using the ELIPSE process to destroy a wide variety of liquids such as tributylphosphate, trichloroethylene, and perfluoro-polyether with an efficiency of over 99% at rates of several liters per hour. The apparent absence of any corrosion observed in the treatment system would indicate that, following optimization, a universal and compact process may soon be available, which may be transportable and dedicated to the treatment of orphan waste products awaiting treatment. (authors)