The vitrification of high level liquid waste (HLLW) resulting from the reprocessing of spent fuel is carried out, in part, in a furnace known as an inductive cold crucible melter at 1200 ° C. The waste initially in liquid form is introduced into the oven after a drying and calcination step.
The work of this thesis is part of studies aiming to feed the waste in the furnace directly in liquid form. The first objective is to be able to simulate the mixture between molten glass and liquid waste at the surface from the point of view of fluid mechanics, thermal and chemical engineering.
The second objectives is to simulate thixotropic behavior of the glass. Experimental data are already available, the law of viscosity of the glass will be a function of time and local shear rate.
This modeling will be integrated into the magneto-thermo-hydraulic simulations of the processes already developed in the laboratory [1-3]. Comparisons between simulations and prototype experiments at a 1: 1 scale inactive, as well as discussions with American and Czech research teams are planned.
[1] Barba Rossa, Thèse de doctorat, Modélisation multiphysique de l’élaboration de verre en creuset froid, 2018, https://www.theses.fr/2017GREAI050
[2] Paraiso K, Sauvage E, Schuller S, Hocine S, Lemaitre V, Burov E. Characterization and modeling of chemical reactions taking place during the vitrification of high level nuclear waste. Journal of Nuclear Materials. 2022, 569, 153878
[3] Pereira Machado, N.M., Neyret, M., Lemaître, C. et al. Thixotropic behavior of a glass melt of nuclear interest containing platinum group metal particles. Rheol Acta (2022). https://doi.org/10.1007/s00397-022-01372-x
[4] Chun, J.; Pierce, D. A.; Pokorny, R. & Hrma, P.; Cold-cap reactions in vitrification of nuclear waste glass Experiments and modeling; Thermochimica Acta , 2013, 559, 32 – 39