In recent years, interest in molten salt nuclear reactors (MSR) has been revived in France and abroad, and the use of chlorinated salts is now being considered. Irrespective of the technological issues to their development, the credibility of this approach depends on the controlled management of the final waste produced during the operation of such reactors. This involves a conditioning stage, which needs to be developed in line with the nature of the waste in question.
The conditioning of two types of waste, resulting from the treatment of spent fuel from a NaCl-MgCl2 molten salt reactor according to different scenarios, is the subject of this post-doctorate, which will be structured in two distinct directions.
The first part of the post-doctorate is dedicated to the vitrification of solutions with complex compositions and enriched in magnesium compared to the usual vitrified fluxes. For this purpose, an aluminoborosilicate matrix is being considered. In order to validate the feasibility of such vitrification, it is essential to assess the microstructure, structure and chemical durability of the resulting glasses, with regard to the expected magnesium contents. Thus, a series of aluminoborosilicate glasses with variable magnesium content will be developed and characterized. The study of these glasses alteration in aqueous solution will be coupled with their structural characterization (Raman, RMN).
The second line of the post-doctorate is dedicated to the conditioning of chlorinated waste, in particular alkaline and alkaline-earth chlorides. In this case, the conditioning method currently favored is ceramization, and will be the subject of a bibliographic study. The chosen route(s) will be tested and characterized, and its containment performance determined.
Skills required: materials science, glass, ceramics, taste for experimentation. Knowledge of Raman will be appreciated.