A review of French vitrification industrial achievements

Since the end of the 50's, research has been ongoing in France to immobilize High Level Waste into a stable and durable waste form. Very early, borosilicate glass was selected as the best compromise between technological feasibility and long term performance. In parallel, the first developments were initiated to design a robust technology able to produce this waste form in the very demanding environment of High Level Waste industrial facilities. These developments led to the start-up of the first industrial HLW vitrification facility based on a calciner and a hot, induction-heated, metallic crucible, at Marcoule (AVM) in 1978. Based on the lessons learned from operating this facility, the technology was further improved to be compatible with a large commercial facility. The R7 facility came into active operation at La Hague, France, in 1989, followed very closely by the WVP facility in Sellafield, UK, which uses the same core technology, and then by the sister facility of R7, T7, which was started in 1992 at La Hague. Since then, these facilities have been operated continuously, while implementing improvements all along their operation life. In parallel, and in order to deal with new waste streams and new industrial requirements, a technology based on cold crucible induction melter was developed and finally implemented in one of the R7 lines in 2010. In parallel with the development of the technology, a specific waste form, the R7T7 glass, was designed, tested, and qualified for this application. The resulting product is a good compromise between industrial feasibility in the technology, flexibility towards waste composition and fuel burn-up evolutions, long term behavior in geological disposal conditions, and waste volume optimization to minimize the burden on the overall glass product management chain, from interim storage to transportation and geological disposal. The paper will describe the technology and logic of these developments, the lessons learned from operation and the corresponding path of improvements, including for maintenance and operation management, and summarize the major operation results to date. (author)