Chemistry of Glass "Part 8": Glass as a fission product solution confinement material!

Cold crucible technology opens the door to a large increase in glass production capacity as well as the creation of unusual confinement matrices with a greater integration rate than that of present glasses by enabling higher melting temperatures to be obtained. The range of waste that can be comprised can be increased while volumes may be decreased using this approach.

The CEA began conducting research to find solutions to the issues raised by the potential use of fission products at the end of the 1950s. In the sixties, glass was chosen as a material for containing solutions of fission products.

Nuclear waste container model in Deutsches Museum.

Owing to the adaptability of its amorphous form, which makes it possible to contain a variety of chemical components, the international community has decided that glass will be used to contain solutions of fission products. Changing the flow from liquid to solid form is the purpose of conditioning fission product solutions; also, obtaining a material that complies with the storage's safety criteria while minimizing the amount in storage. In this case, it is an issue of confinement on the atomic scale since radionuclides are involved in the structure of the glass. Furthermore, self-irradiation is well resisted by the glass.

About 80% of silicon oxide SiO2, boric anhydride B2O3, alumina Al2O3, and sodium Na2O make up the glass reference R7T7 that Areva NC manufactures. The solution of fusion products from the processing of light water reactor (LWR) fuel is actually confined in this type of glass. The compositions of inactive simulating glass were used to estimate the physicochemical characteristics of R7T7 glass, they were then verified with laboratory-made samples of radioactive glasses.

References:

• CHARACTERIZATION OF THE R7T7 LWR REFERENCE GLASS- PACAUD F.- FILLET C.- BAUDIN G. CEA Centre d'Etudes Nucléaires de la Vallée du Rhône, 30 Bagnols-sur-Ceze ^FR
• [General and inorganic chemistry book- M. Shkhashirou- H. Birqdad- Y. Qodsi- University publications. Algeria]
• Glass and Ceramic Technology Course (2021). Professor Khelifa- Department of Materials Process Engineering- University of Mostaganem. Algeria.
• Les matériaux au cœur du processus d'innovation- Clefs CEA No 59.
• Neumann, Florin. "Glass: Liquid or Solid – Science vs. an Urban Legend". Archived from the original on 9 April 2007. Retrieved 8 April 2007.
• Helène Tregouët. Structure et cristallisation de verres d’oxydes simples riches en bore et en terres rares. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie- Paris VI, 2016. Français. NNT: 2016PA066032. tel-01358710.