DEVELOPMENT OF VITRIFICATION PROCESS AND GLASS FORMULATION FOR NUCLEAR WASTE CONDITIONING

摘要

The vitrification of high-level waste is the internationally recognized standard to minimize the impact to thernenvironment resulting from waste disposal as well as to minimize the volume of conditioned waste to be disposed of.rnCOGEMA has been vitrifying high-level waste industrially for over 20 years and is currently operating threerncommercial vitrification facilities based on a hot metal crucible technology, with outstanding records of safety,rnreliability and product quality. To further increase the performance of vitrification facilities, CEA and COGEMArnhave been developing the cold crucible melter technology since the beginning of the 1980s. This type of melter isrncharacterized by a virtually unlimited equipment service life and a great flexibility in dealing with various types ofrnwaste and allowing development of high temperature matrices.rnIn complement of and in parallel with the vitrification process, a glass formulation methodology has been developedrnby the CEA in order to tailor matrices for the wastes to be conditioned while providing the best adaptation to thernprocessing technology. The development of a glass formulation is a trade-off between material properties andrnqualities, technical feasibility, and disposal safety criteria. It involves non-radioactive and radioactive laboratories inrnorder to achieve a comprehensive matrix qualification.rnSeveral glasses and glass ceramics have thus been studied by the CEA to be compliant with industrial needs andrnwaste characteristics: glasses or other matrices for a large spectrum of fission products, or for high contents ofrnspecifics elements such as sodium, phosphate, iron, molybdenum, or actinides. New glasses or glass-ceramicsrndesigned to minimize the final wasteform volume for solutions produced during the reprocessing of high burnuprnfuels or to treat legacy wastes are now under development and take benefit from the latest CEA hot-laboratories andrntechnology development. The paper presents the CEA state-of-the-art in developing matrices or glasses and providesrnseveral examples