Conclusion

Vitrification of radioactive waste

Figure 1 - Differences in the chemical composition of glass, source CEA

Figure 2 - Scanning electron microscope image of the final glass, after homogenization, source CEA

Figure 3 - SPNM glass microstructure as seen by scanning electron microscope (backscattered electron image)

Figure 4 - Simplified cross-section of the structure of a glassy lattice with 4 SiO2 oxides—B2O3—Al2O3—Na2O, from [9]

Figure 5 - Evolution of the viscosity of R7T7 glass cast irons, with and without noble metal particles (platinoids), measured between 950°C and 1,150°C, source CEA

Figure 8 - Theoretical maximum percentages by volume of crystalline phases occurring during devitrification heat treatment of R7T7 nuclear glass, based on [6]

Figure 9 - Nucleation curves and growth curves for the ZnCr2O4 phase in glass with platinoids and without platinoids, according to. [6]

Figure 10 - Evolution of the hardness of different R7T7 glass samples (doped with different levels of 244CmO2), as a function of the number of alpha disintegrations per gram of glass, from [7]

Figure 11 - Initial dissolution velocity V0 in pure water at 100°C of 244Cm-doped R7T7 glass, as a function of cumulative alpha decay number, from [7]

Figure 13 - Schematic representation of the different stages in the weathering kinetics of silicate glass, from [8]

Figure 14 - Evolution of the initial dissolution rate (in g · m–2· j–1) of glass type R7T7 in water, as a function of pH, at 50, 90 and 150°C, source CEA

Figure 16 - Basalt glass from Salagou (from [12]) and ancient Roman glass

Figure 17 - Principle of the French two-stage vitrification process used at La Hague, source AREVA NC

Figure 18 - Schematic of calciner R7T7, source AREVA NC

Figure 19 - Diagram and view of the R7T7 melting pot

Figure 20 - Melting pot remotely removed from heating furnace (Workshop R7)

Figure 21 - Volume of fines in the tanks at the UP3 plant in La Hague, France

Figure 22 - Cumulative production of workshop R7 (number of packages produced)

Figure 23 - Schematic diagram of direct induction melting in a cold crucible, source CEA

Figure 24 - Internal view of sectorized metal ferrule

Figure 25 - Schematic diagram of the cold crucible developed by CEA and AREVA for AREVA&#039;s industrial applications at La Hague, source AREVA NC

Figure 26 - The furnace at the Defense Waste Processing Facility (DWPF) in Savannah River, USA, Image DOE

Figure 27 - Evacuation of the first DWPF furnace at Savannah River, DOE Image