Development of a Dosage System for the Incineration of Radioactive and Particle-laden Liquid - 18080

The alpha incinerator has been operating since 1999 at the CEA Valduc center in France for the treatment of alpha-bearing technological waste. The fact that the incinerator has been working smoothly for 18 years and the experience gained during this period indicate that it can also be used to treat other types of waste, such as Ion-Exchange Resin (IER) suspensions. The aims of an R and D project initiated in 2014 were to develop a dosage system allowing these suspensions to be injected into the heart of the treatment system and to evaluate the performance of the incinerator when these materials are added to technological waste. This article describes the work carried out to develop a dosage system for heavily particle-laden fluids (with more than 50 vol% solid particles), with the aim of delivering waste continuously into the treatment furnace. The proposed device consists of a feeding tank equipped with a stirrer, a piston pump, and a pneumatic transport system. Reliability has been improved by replacing the initial sealing system (a piston with seals), by a very tight (∼4 μm gap), therefore seal-less, sleeve/piston unit. Adjusting the carrying gas flow has optimized the system as a whole, making it safer and more robust. The system has been qualified through more than 1000 hours of operation and the results obtained for the incineration of IER suspensions suggest that industrial transport is feasible and will thus begin soon. (authors)